Ordinary constipation does not directly cause chills, but the two symptoms show up together more often than you might expect. The connection usually runs through one of two paths: either an underlying condition is simultaneously slowing the gut and disrupting temperature regulation, or constipation has become severe enough to trigger an inflammatory or infectious response that produces chills as a warning sign. Understanding which scenario applies matters, because one is manageable with routine care and the other can become a medical emergency.
How a Shared Underlying Condition Can Produce Both Symptoms
The most common reason people experience constipation and chills at the same time is that a single disease is driving both. Your gut doesn’t operate independently from the rest of your body. Hormonal, immune, and neurological systems all influence how quickly food moves through your intestines and how well your body manages its own temperature. When one of those systems malfunctions, you can end up with sluggish bowels and feeling cold at the same time, even though one symptom isn’t causing the other.
Hypothyroidism is perhaps the most familiar example. An underactive thyroid slows metabolism across the board: digestion slows down, leading to constipation, and the body’s ability to generate heat drops. Researchers studying hypothyroid patients found that cold-induced thermogenesis, the body’s heat-production response when exposed to cool temperatures, roughly doubled after thyroid hormone levels were restored to normal. Energy expenditure in cool conditions jumped by about 15% once patients were treated, confirming that the cold sensitivity hypothyroid patients report is a measurable, physiological deficit, not just a subjective complaint.1PubMed Central. Resolution of Hypothyroidism Restores Cold-Induced Thermogenesis in Humans So if you’re constipated and also feel unusually cold or get chills easily, hypothyroidism is one of the first things worth investigating, particularly if you also notice fatigue, dry skin, or unexplained weight gain.
Autoimmune and connective tissue disorders offer another route. Systemic sclerosis, for instance, typically begins with Raynaud’s phenomenon, where blood vessels in the fingers and toes overreact to cold and trigger painful chills and color changes. The same disease process also damages the gastrointestinal tract, with the esophagus being the most frequently affected organ and the colon not far behind.2Europe PMC / Przegląd Gastroenterologiczny. Systemic sclerosis and the gastrointestinal tract Patients with systemic sclerosis often deal with chronic constipation because the intestinal muscles lose their ability to contract normally. For someone in this situation, chills and constipation aren’t cause-and-effect; they’re co-passengers of the same autoimmune process.
When Severe Constipation Creates a Real Emergency
While mild or moderate constipation won’t cause chills on its own, constipation that has been left untreated for a long time can progress into something genuinely dangerous. This is where the relationship flips: the constipation itself leads to a complication that triggers chills, fever, and other signs of a body-wide inflammatory response.
The condition most directly linking severe constipation to chills is stercoral colitis, an inflammation of the colon wall caused by a large, hardened mass of stool pressing against the intestinal lining. As that mass compresses blood vessels in the colon wall, the tissue can become ischemic, meaning its blood supply gets cut off. Patients with stercoral colitis can develop abdominal pain, distension, nausea, and vomiting, but when complications set in, the symptoms escalate to fever, chills, rectal bleeding, and dangerously low blood pressure.3Radiology Case Reports / Elsevier. Stercoral colitis due to massive fecal impaction: a case report and literature review The chills in this case are a classic sign of a systemic infection response: bacteria from the damaged colon wall are getting into the bloodstream.
If the pressure continues, the colon wall can actually perforate. Stercoral perforation is a life-threatening surgical emergency because contaminated intestinal contents spill into the abdominal cavity, leading to peritonitis and rapid bacteremia.4PubMed Central. Stercoral perforation of the rectosigmoid colon due to chronic constipation: A case report At that point, chills aren’t just a symptom; they’re part of a cascade that can be fatal without immediate intervention. This scenario is uncommon, but it underscores why longstanding, severe constipation in elderly or immobile patients should be taken seriously rather than dismissed as a minor inconvenience.
Intestinal obstruction is another severe endpoint of chronic constipation. When the bowel becomes completely blocked, the risk of infection climbs sharply. A study of patients who underwent surgery for intestinal obstruction found that about 16% developed postoperative sepsis, and patients with elevated markers of pre-existing systemic inflammation had roughly double the odds of that outcome.5PubMed Central. Association between preoperative systemic immune inflammation index and postoperative sepsis in patients with intestinal obstruction Sepsis, of course, produces shaking chills, high fever, and can lead to organ failure if untreated. The takeaway is straightforward: complete inability to pass stool combined with chills, fever, or severe abdominal pain warrants emergency medical attention.
The Gut-Brain Axis and Why Constipation Affects How You Feel
Even in the absence of infection or a named disease, chronic constipation involves more than just the colon. The gut and the brain are in constant two-way communication through what researchers call the brain-gut-microbiome axis. Serotonin, the same chemical most people associate with mood, plays a central role in this communication, and most of the body’s serotonin is actually produced in the gut, not the brain. Chronic constipation involves disruptions in serotonin signaling, specifically in how it is made, released, and detected by receptors along the intestinal wall.6Frontiers in Medicine (Europe PMC). Chronic constipation and the brain-gut-microbiome axis: the role of 5-HT signaling and Traditional Chinese Medicine in pathophysiology and treatment Because serotonin influences not only gut motility but also mood, pain perception, and autonomic nervous system activity, a sustained disruption in serotonin dynamics can produce symptoms that feel like they have nothing to do with digestion.
The autonomic nervous system, the part of your nervous system that controls involuntary functions like heart rate, sweating, and body temperature, is particularly relevant here. When the colon is severely distended, it sends distress signals up to the brain through specific neural circuits. Experiments in animal models have shown that stretching the colon activates the locus coeruleus, a region in the brainstem that controls the body’s arousal and stress response. When the pathway between the gut and this brain region was intact, colon distension increased the firing rate of stress-response neurons by about 27%; when researchers disrupted the relay, the effect nearly disappeared.7Elsevier / PubMed Central. Role of Barrington’s nucleus in the activation of rat locus coeruleus neurons by colonic distension In practical terms, this means that a backed-up, bloated colon can trigger genuine stress and autonomic responses: sweating, nausea, lightheadedness, and yes, chills. These responses are your nervous system reacting to what it interprets as an internal threat, not a sign that the constipation itself has become infectious.
This is a useful distinction. Autonomic-driven chills from a distended bowel tend to be milder, transient, and associated with a bowel movement attempt or a particularly uncomfortable bout of bloating. Infection-driven chills tend to be more severe, accompanied by fever, and don’t resolve once gas or stool passes. The nervous system can make you feel genuinely awful during a bad episode of constipation, but those symptoms usually ease once the constipation is relieved.
Methane, Gut Bacteria, and the Slowest Guts
Not all constipation is created equal, and the composition of your gut bacteria influences just how sluggish things get. Some people harbor bacteria that produce methane gas in unusually high amounts, and methane directly slows the contractions that push stool through the colon. A recent study using breath testing to measure methane production found three distinct patterns among patients evaluated for gut motility problems. The “high-producer” group, whose breath methane started at a median of 31 parts per million and climbed steeply during testing, had slow colonic transit nearly 70% of the time. By contrast, the “non-producer” group, with negligible methane output, had slow transit only about 29% of the time. After adjusting for other factors, high methane production was independently associated with more than five times the odds of slow transit.8Europe PMC. Methane Trajectory Phenotypes on Glucose Breath Testing Are Associated With Slow Colonic Transit
What does this have to do with chills? Mostly it helps explain why some people’s constipation is so stubborn that it reaches the severity levels described in the previous sections. High methane producers are disproportionately likely to develop the kind of prolonged, treatment-resistant constipation that can escalate into impaction, colitis, or obstruction. If you’ve tried standard remedies like fiber, hydration, and over-the-counter laxatives without improvement, methane overproduction from intestinal bacteria may be part of the picture. It also partly explains why antibiotics targeted at methane-producing organisms have shown promise for certain patients with chronic constipation, though that treatment approach is still being refined.
Medications That Cause Both Constipation and Chills
A number of commonly prescribed medications can cause constipation as a side effect. Opioid painkillers are the most well-known culprit, but calcium channel blockers, certain antidepressants, iron supplements, and some antacids can also slow the gut. When someone taking one of these medications also experiences chills, the question becomes whether the chills are from the same drug, from the underlying condition being treated, or from a complication of the constipation itself.
Opioids are an instructive case. They cause constipation in a large proportion of people who take them because they activate receptors in the gut wall that slow intestinal contractions and reduce fluid secretion. At the same time, opioids affect the body’s thermoregulatory system: they can cause sweating, flushing, or chills, and opioid withdrawal famously produces intense chills and goosebumps (the origin of the phrase “cold turkey”). So a person on opioid therapy who is constipated and experiencing chills may be dealing with a drug side effect, early withdrawal between doses, or a constipation complication, and the clinical picture can be confusing even for physicians.
Chemotherapy is another scenario where both symptoms commonly co-occur. Many chemotherapy agents cause severe constipation, and the immune suppression they produce makes patients more vulnerable to infections that cause fever and chills. In this context, chills accompanying constipation in a patient on chemotherapy should always be evaluated promptly, because even a low-grade fever in an immunocompromised person can signal a dangerous infection.
How to Tell When the Combination Is Serious
If you’re mildly constipated and get an occasional chill, you’re almost certainly dealing with coincidence or a mild autonomic response. But certain combinations of symptoms should prompt you to seek medical attention quickly:
- Fever above 101°F (38.3°C): Fever with constipation suggests an infectious or inflammatory process, especially if accompanied by shaking chills.
- Severe abdominal pain: Pain that is sudden, sharp, or worsening can indicate obstruction, perforation, or ischemia of the bowel wall.
- No stool or gas for days: Complete absence of both stool and gas passage suggests a full obstruction, not just sluggish motility.
- Vomiting with constipation: When the gut is blocked, contents can back up far enough to cause vomiting, which adds dehydration risk on top of the obstruction.
- Rapidly worsening symptoms: A situation that progresses from discomfort to severe pain and chills over hours rather than days may involve perforation or sepsis.
Elderly patients, people who are bedridden or have limited mobility, and those on chronic opioid therapy are at the highest risk for constipation progressing to dangerous complications. In these populations, caregivers should monitor bowel habits closely rather than assuming infrequent stools are harmless.
Conditions People Mistake for “Constipation With Chills”
Sometimes what feels like constipation paired with chills is actually a different condition masquerading as both. Gastroenteritis, or a stomach bug, can cause chills as part of the infectious response and simultaneously slow gut motility or cause the feeling of incomplete evacuation. People sometimes interpret the bloating, cramping, and reduced stool output of early gastroenteritis as constipation, when in reality diarrhea is just a few hours away.
Appendicitis is another mimic. Early appendicitis can cause vague abdominal discomfort, loss of appetite, and a sense that the bowels aren’t moving normally. Chills and low-grade fever may appear before the classic right-lower-quadrant pain develops. Because the early symptoms are nonspecific, patients sometimes self-diagnose constipation and try home remedies, delaying evaluation of what turns out to be a surgical problem.
Pelvic infections, diverticulitis, and inflammatory bowel disease flares can all produce a similar overlap of altered bowel habits and systemic symptoms like chills. The through-line is that any abdominal condition involving inflammation or infection can slow the gut reflexively while simultaneously producing fever and chills through the immune response. Constipation in these situations is a secondary effect of the inflammation, not the primary problem. Treating the constipation without addressing the underlying cause misses the point entirely.
Chronic Constipation and Feeling Cold All the Time
A related but distinct complaint from acute chills is the experience of feeling persistently cold. People with longstanding chronic constipation sometimes report that they always feel colder than the people around them, and they wonder whether their gut issues are to blame. The answer is nuanced. Chronic constipation by itself probably isn’t making you cold, but the metabolic and hormonal conditions that predispose you to chronic constipation can absolutely reduce your baseline body temperature and impair your ability to warm up.
Hypothyroidism, as discussed earlier, is the most direct example: it slows the gut and reduces heat production simultaneously. But even without a formal thyroid diagnosis, people who eat very little, whether from restrictive dieting, disordered eating, or simply poor appetite, can develop both chronic constipation from insufficient dietary bulk and a reduced metabolic rate that makes them feel perpetually chilled. The body conserves energy by turning down non-essential functions, and heat production and gut motility are both on the list of things it’s willing to sacrifice.
Iron deficiency anemia, which can develop from poor dietary intake or from chronic low-grade blood loss in the GI tract, also causes cold sensitivity alongside fatigue and sometimes altered bowel habits. The connection to constipation is less direct here, but a patient presenting with both complaints is worth screening for anemia as well as thyroid dysfunction. In all of these cases, the constipation and the cold intolerance are fellow symptoms, not a causal chain, and addressing the root metabolic issue resolves both.