Andrographis is a bitter-tasting herb native to India and Sri Lanka that has been used for centuries to treat fevers, infections, and digestive complaints. Known as the “King of Bitters,” it’s now one of the more widely studied herbal supplements for upper respiratory infections like the common cold. Most of its medicinal effects come from a compound called andrographolide, found primarily in the plant’s leaves.
The Plant and Its Active Compounds
Andrographis paniculata is an annual herb in the Acanthaceae family that grows about half a meter to one meter tall. While it originated in peninsular India and Sri Lanka, it now grows across Southeast Asia, China, the West Indies, and parts of the Americas. It goes by different names depending on the region: kalmegh in Bengali, Fah Talai Jone in Thai, and Mahatikta in Sanskrit.
The plant’s therapeutic value comes from a group of compounds called diterpene lactones, with andrographolide being the most abundant and most studied. In a crude extract, andrographolide typically makes up roughly 38 mg per gram of material, though concentrated fractions can push that above 85 mg per gram. Three related compounds (neoandrographolide, 14-deoxy-11,12-didehydroandrographolide, and andrograpanin) also contribute to the plant’s effects but are present in lower amounts.
How It Works in the Body
When you take andrographis orally, the andrographolide is absorbed relatively quickly. Blood levels peak about 1.5 to 2 hours after a dose, and the compound has a half-life of roughly 6.6 hours, meaning it stays active in your system for a meaningful window before being cleared. This pharmacokinetic profile is part of why dosing is typically split across the day rather than taken all at once.
Andrographolide appears to work through multiple pathways. It modulates the immune system’s inflammatory response and has shown antibacterial and antifungal properties in lab studies. For respiratory infections specifically, it seems to reduce the severity of the immune system’s reaction to a virus, which is what causes most cold symptoms, rather than killing the virus directly.
Evidence for Cold and Flu Symptoms
The strongest clinical evidence for andrographis is in treating uncomplicated upper respiratory infections. A systematic review of randomized controlled trials involving 433 patients found that andrographis extract was significantly more effective than placebo at reducing symptom severity, with the difference large enough to be clinically meaningful (not just statistically detectable).
One double-blind placebo-controlled study measured individual symptoms using visual analog scales and found notable improvements starting as early as day two of treatment. By day two, participants taking a standardized andrographis extract experienced significantly less tiredness, sleeplessness, sore throat, and nasal congestion compared to the placebo group. By day four, all measured symptoms had improved significantly. Sore throat showed the largest effect, with participants in the andrographis group about 3.6 times more likely to report improvement than those on placebo. Nasal secretion and earache followed close behind.
These results are promising but come with caveats. The total number of trials is still relatively small, and most have been short-term, focusing on acute illness rather than prevention. Andrographis does not appear to prevent you from catching a cold. Its value is in shortening how long symptoms last and reducing how severe they feel once you’re already sick.
Typical Dosing
Most clinical research has used standardized extracts dosed by their andrographolide content rather than by total plant material, which matters because raw herb potency varies widely. For uncomplicated upper respiratory infections, the commonly studied dose is 60 mg of andrographolide per day for adults and 30 mg per day for children. For more significant throat inflammation, studies have used up to 180 mg per day.
Supplement labels can be confusing because some list total extract weight while others list the andrographolide content specifically. A product standardized to contain a certain percentage of andrographolides will tell you both numbers. If the label only lists total milligrams of andrographis extract, you’ll need to check what percentage is standardized to andrographolides to calculate your actual dose of the active compound.
Side Effects and Safety Concerns
At standard oral doses, andrographis is generally well tolerated. The most common side effects are gastrointestinal: nausea, diarrhea, loose stools, and a bitter or metallic taste. Some people report headache, fatigue, dizziness, or skin itching. These tend to be mild and resolve after stopping the supplement.
The more serious concern is allergic reactions. Australia’s Therapeutic Goods Administration has been tracking this issue closely. Since 2005, the agency has received over 300 reports of anaphylaxis or hypersensitivity reactions to andrographis-containing products, with more than 200 of those reports coming since 2019. In June 2024, the TGA reported a fatal anaphylactic reaction linked to an andrographis product and issued a safety advisory. This doesn’t mean andrographis is broadly dangerous, but it does mean allergic reactions are not as rare as once thought. If you’ve never taken andrographis before, starting with a small dose to check for a reaction is a reasonable precaution. Anyone with a history of allergic reactions to herbal supplements should be particularly cautious.
Andrographis may also interact with blood-thinning medications and drugs that suppress the immune system, since it has both antiplatelet and immune-modulating properties. People taking anticoagulants or immunosuppressants should talk to a pharmacist before adding it to their regimen.
How It Compares to Other Cold Remedies
Andrographis occupies a similar space to echinacea and zinc lozenges: supplements people reach for at the first sign of a cold. Its evidence base for symptom reduction is arguably stronger than echinacea’s, with more consistent results across trials. The key advantage is how quickly it appears to work, with measurable symptom improvement by day two in clinical studies. The key disadvantage is the allergy risk, which is more notable than for most herbal cold remedies. It also won’t help with the flu specifically, as the clinical trials have focused on uncomplicated upper respiratory infections rather than influenza.