What Are Salicylates Drugs? Uses and Side Effects

Salicylates are a family of drugs derived from salicylic acid, a compound originally extracted from willow bark, that reduce pain, fever, and inflammation. The most familiar member is aspirin (acetylsalicylic acid), but the family also includes topical salicylic acid used for skin conditions, salsalate prescribed for arthritis, bismuth subsalicylate found in over-the-counter stomach remedies, and methyl salicylate rubbed on sore muscles. What ties these drugs together is a shared chemical backbone and a common ability to interfere with the body’s production of prostaglandins, the signaling molecules behind pain, swelling, and fever. Their uses, their side effects, and the situations where they become dangerous are broader and more varied than most people realize.

Where Salicylates Come From

The use of salicylate-containing plants for pain and fever stretches back more than 3,500 years. Ancient Sumerians, Egyptians, and Greek physicians used willow bark preparations as painkillers and fever reducers.¹ The modern chapter started in 1763, when an English clergyman named Edward Stone described willow bark’s ability to bring down fever. Over the following century, chemists isolated salicylic acid, and in 1897 a Bayer chemist named Felix Hoffmann synthesized acetylsalicylic acid, which was easier on the stomach than pure salicylic acid.² Aspirin went on to become the most commonly used drug in the world, but researchers continued developing other salicylate forms for different clinical needs, from topical skin treatments to gastrointestinal remedies.

How Salicylates Work in the Body

The best-understood mechanism of aspirin is its ability to block cyclooxygenase, or COX, the enzyme that converts fatty acids in your cells into prostaglandins. Prostaglandins do many things: they trigger inflammation at injury sites, sensitize nerve endings to pain, raise your body’s thermostat during illness, and help regulate blood flow in the kidneys and stomach lining. Aspirin permanently disables COX by chemically modifying the enzyme in a way that cannot be undone, which is why a single dose can suppress platelet clumping for the entire lifespan of those platelets, roughly 7 to 10 days.³

Other salicylates work somewhat differently. Sodium salicylate, for instance, is a weak direct inhibitor of COX activity, yet it still reduces inflammation effectively. Research has shown that sodium salicylate suppresses COX-2 at the level of gene expression, blocking the messenger RNA that cells use to produce the enzyme in the first place.⁴ Salicylate metabolites, including gentisic acid (a breakdown product of salicylic acid in the body), also suppress prostaglandin production through their own pathways.⁵ The upshot is that the salicylate family attacks inflammation from multiple angles, not just the one mechanism most people associate with aspirin.

Common Medical Uses

Salicylates are prescribed or recommended for a wide range of conditions. Here are the main ones:

• Pain and fever: Over-the-counter aspirin remains widely used for headaches, muscle aches, dental pain, and fevers in adults. Because it is inexpensive and well understood, it is a go-to option when stronger drugs are not needed.
• Cardiovascular protection: Low-dose aspirin is a cornerstone of secondary prevention for people who have already had a heart attack or stroke. Meta-analyses of large trials have found that aspirin reduces the risk of a subsequent heart attack by about 30% and stroke by roughly 20%.⁶ Similar pooled analyses confirm that aspirin lowers the risk of coronary heart disease and stroke by around 20% in these populations.⁷ Its anti-clotting effect comes from blocking the production of thromboxane A2, a chemical that makes platelets sticky.
• Arthritis: Salsalate, a nonacetylated salicylate, is sometimes prescribed for rheumatoid arthritis or osteoarthritis. It provides anti-inflammatory relief while having a gentler effect on the stomach and platelets than aspirin.
• Skin conditions: Topical salicylic acid is used as a keratolytic, meaning it softens and helps shed the outer layer of skin. It is a standard treatment for acne, warts, psoriasis, and dandruff.⁸
• Stomach and intestinal problems: Bismuth subsalicylate, the active ingredient in medications like Pepto-Bismol, is used for indigestion, nausea, and diarrhea. It also plays a role in treating the bacterium Helicobacter pylori, which causes stomach ulcers.

Beyond these established roles, salicylates are being investigated for potential anticancer, neuroprotective, and antidiabetic effects, though those applications are still in the research phase.⁹

Bismuth Subsalicylate and Gut Health

Bismuth subsalicylate deserves its own discussion because it works differently from other salicylates. The bismuth component coats the stomach lining and acts directly against bacteria, while the salicylate portion reduces inflammation in the gut. Together they address multiple causes of stomach distress at once.

For travelers’ diarrhea, a meta-analysis found that people taking bismuth subsalicylate had about 3.5 times greater odds of avoiding diarrhea compared with placebo. Among those who already had infectious diarrhea, treatment gave roughly 3.7 times greater odds of symptom relief.¹⁰ In the context of H. pylori eradication, bismuth-containing regimens can overcome antibiotic resistance that derails standard treatments. Bismuth-containing quadruple therapy achieves eradication rates above 90%, and international guidelines recommend it as a first-line option in regions where antibiotic resistance is high.¹¹

Side Effects of Salicylates

Because prostaglandins protect the stomach lining and regulate blood flow to the kidneys, blocking them creates predictable problems. The most common side effects of oral salicylates include stomach irritation, nausea, and heartburn. With prolonged use or higher doses, aspirin can cause gastric erosions and ulcers, sometimes leading to bleeding that the person does not immediately notice. This gastrointestinal risk is the main reason aspirin is often taken with food or in enteric-coated forms.

A less obvious side effect is hearing disturbance. At higher therapeutic doses (the kind used historically for rheumatic fever or severe arthritis), salicylates can cause tinnitus, a persistent ringing in the ears, and temporary hearing loss. Research has traced this to salicylate’s effect on the outer hair cells in the cochlea: the drug increases the permeability of these cell membranes, which disrupts a feedback mechanism called the cochlear amplifier and reduces hearing sensitivity.¹² The good news is that this effect is dose-dependent and fully reversible once the drug is stopped or the dose is lowered. Tinnitus is actually used clinically as a warning sign that a patient’s salicylate dose is near the upper limit of the safe range.

Kidney problems are another concern, especially in people whose kidneys already depend on prostaglandins to maintain adequate blood flow. In patients with pre-existing kidney disease, even nonacetylated salicylates like salsalate can cause an abrupt decline in kidney function. One study documented a parallel decline in prostaglandin excretion and kidney function during salsalate treatment, with rapid recovery after the drug was stopped.¹³ Older adults, people taking diuretics, and anyone with chronic kidney disease are at heightened risk.

Aspirin and Children

One of the sharpest restrictions on salicylate use involves children and teenagers. Since the early 1980s, aspirin has been discouraged for treating fevers or viral illnesses in young people because of an association with Reye syndrome, a rare but potentially fatal condition that causes swelling of the liver and brain. Case-control studies from that era found that children with Reye syndrome were substantially more likely to have taken aspirin-containing products during the preceding viral illness than matched controls.¹⁴ Additional case-control data suggested that administering aspirin during a prodromal viral infection increased the risk of this devastating condition.¹⁵

Some researchers have argued that a definitive causal link was never proven beyond epidemiological association.¹⁶ Regardless, the practical result has been decisive: public health agencies recommend against giving aspirin to anyone under 18 during a fever or viral illness, and the incidence of Reye syndrome has plummeted since that guidance was adopted. Acetaminophen and ibuprofen have replaced aspirin as the standard pediatric fever reducers.

Aspirin Sensitivity and Samter’s Triad

Some people cannot tolerate aspirin or other salicylates at all. True aspirin sensitivity is not a classic allergy involving the immune protein IgE. Instead, it is thought to stem from an imbalance in the way COX inhibition shifts the production of inflammatory mediators called leukotrienes. When COX is blocked in these individuals, the leukotriene pathway goes into overdrive, causing nasal congestion, asthma attacks, and sometimes hives or facial swelling.

The most well-known form is Samter’s triad, which involves the combination of asthma, nasal polyps, and aspirin intolerance.¹⁷ People with this condition often react not only to aspirin but also to other nonsteroidal anti-inflammatory drugs that inhibit COX-1, such as ibuprofen and naproxen. For individuals with Samter’s triad, a supervised aspirin desensitization protocol can sometimes retrain the body’s tolerance, allowing daily aspirin use and in many cases reducing nasal polyp recurrence. But the desensitization must be done in a medical setting because the initial challenge doses can provoke a severe asthma flare.

Acetylated Versus Nonacetylated Salicylates

Not all salicylates behave the same way, and the distinction between acetylated and nonacetylated forms matters for side-effect profiles. Aspirin is the only acetylated salicylate. It permanently modifies COX by transferring an acetyl group onto the enzyme. This is why a single dose of aspirin shuts down platelet activity for the entire life of those blood cells.

Nonacetylated salicylates, like salsalate and sodium salicylate, bind COX reversibly and have minimal effect on platelet function. A study comparing aspirin and salsalate in human subjects found that salsalate barely affected platelet-derived prostaglandin levels, while aspirin profoundly suppressed them. When the drugs were discontinued, salsalate’s effects reversed within 36 hours, whereas recovery from aspirin was still incomplete after 13 days.¹⁸ This has practical consequences: if you need anti-inflammatory relief but are at risk for bleeding, or if you are scheduled for surgery, a nonacetylated salicylate is far less likely to cause excessive bleeding than aspirin. Sodium salicylate can also suppress COX-2 induction through mechanisms that do not depend on the NF-kappaB pathway.¹⁹

Low-Dose Aspirin in Pregnancy

One area where aspirin has gained ground in recent decades is the prevention of preeclampsia, a dangerous pregnancy complication involving high blood pressure and organ damage. A large trial found that daily low-dose aspirin (150 mg), started before 16 weeks of pregnancy in women identified as high risk by a first-trimester screening test, reduced the incidence of preterm preeclampsia by about 62%. A secondary analysis of the same trial showed a 68% reduction in neonatal intensive-care stays, driven mainly by fewer very preterm births with preeclampsia.²⁰

A systematic review for the U.S. Preventive Services Task Force confirmed the broader picture: low-dose aspirin reduced preeclampsia risk by about 24%, intrauterine growth restriction by 20%, and preterm birth by 14%, with no significant harms to mother or baby identified.²¹ One earlier trial did observe a higher rate of placental abruption in the aspirin group, though the overall balance of evidence has supported aspirin’s safety profile during pregnancy when used at low doses.²² As a result, professional guidelines now recommend that women at elevated risk for preeclampsia begin low-dose aspirin in the first trimester.

When Aspirin Stops Working

A frustrating reality for cardiologists is that aspirin does not work equally well in everyone. Some people continue to have cardiovascular events despite faithfully taking their daily low-dose aspirin. This phenomenon is sometimes called “aspirin resistance,” though the term covers a range of situations, from true biochemical non-response (the drug does not inhibit platelets as expected) to clinical failure (the patient has an event regardless). Estimates of the resistance rate vary widely depending on how it is measured, but reviews suggest it is not rare.²³

Possible explanations include individual variation in how well the gut absorbs aspirin, interactions with other drugs (ibuprofen, for instance, can compete with aspirin for access to the COX enzyme on platelets), increased platelet turnover in certain conditions like diabetes, and genetic differences in platelet receptors. In the stroke population, inadequate responsiveness to aspirin and other antiplatelet agents correlates with a higher risk of recurrent events.²⁴ Testing for aspirin resistance remains inconsistent in clinical practice, with no single agreed-upon test, and there is limited evidence that switching drugs based on a resistance test improves outcomes. For now, the standard approach is to ensure the patient is taking aspirin consistently, at the right dose, and without interacting medications.

Salicylates in Food

Salicylates are not only pharmaceutical products. Salicylic acid occurs naturally in many plants as part of their defense system against pathogens and environmental stress. Spices and herbs, particularly curry powder and hot paprika, are among the richest dietary sources. Fruits, vegetables, and teas also contain varying amounts. A narrative review found that the dietary intake of salicylates in vegetarians can be high enough to produce blood and urine concentrations of salicylic acid comparable to those seen in patients taking a 75 mg daily aspirin dose.²⁵ This has led to speculation that plant-rich diets may confer some of the cardiovascular and anti-inflammatory benefits associated with low-dose aspirin, though the evidence for this is preliminary.

For most people, dietary salicylates are not a concern. Total food intake is low compared with a therapeutic dose of aspirin.²⁶ However, individuals with aspirin sensitivity or Samter’s triad sometimes report worsening of symptoms on high-salicylate diets. Low-salicylate diets exist for this reason, though the evidence supporting their effectiveness is largely based on case reports and clinical experience rather than rigorous trials. If you have known aspirin sensitivity and notice flares after eating heavily spiced foods, it may be worth discussing dietary salicylate content with your doctor, but wholesale elimination diets can be nutritionally restrictive and are not recommended without guidance.