Walk into a pharmacy in Germany in December and you’ll likely find a remedy most American shoppers have never heard of: Pelargonium sidoides, often sold under the name umckaloabo. It comes from the root of a geranium relative native to South Africa, where it has a long history of traditional use for respiratory complaints. Over the past few decades it has become one of the more thoroughly researched herbal cold and cough remedies.
“More thoroughly researched than most herbs” isn’t the same as proven, though. Here’s an honest look at the evidence.
What pelargonium is
Pelargonium sidoides is a flowering plant in the geranium family. It is not the ornamental geranium on your porch. The medicinal part is the root, which contains coumarins, polyphenols (including tannins), and other compounds.
Most of the clinical research used one specific product: a standardized aqueous-ethanolic root extract known as EPs 7630. That matters. Results from that extract don’t automatically carry over to other pelargonium products, which can vary widely in concentration and composition. For more on why extract standardization matters, see standardized extracts explained.
Proposed mechanisms
In lab studies, pelargonium extracts have shown:
- Effects on how some viruses attach to cells
- Changes in the activity of immune signaling molecules
- Increased beating frequency of cilia, the tiny hairs that clear mucus from the airways
These findings come mostly from test tubes and animal models. They’re a plausible starting point, but they don’t show what happens in a person with a cough.
What the clinical trials show
Acute bronchitis
This is where most of the human research sits. Several randomized, placebo-controlled trials in adults and children with acute bronchitis (bronchitis not requiring antibiotics) reported that people taking the extract had:
- Greater reductions in bronchitis symptom scores, especially cough and sputum, over about a week
- Somewhat faster return to normal activity or work
- Similar rates of mild side effects to placebo
Systematic reviews pooling these trials have generally concluded that pelargonium may relieve acute bronchitis symptoms modestly. They also flagged important weaknesses:
- Many trials were conducted or funded by the manufacturer of the extract, and many came from a small number of research groups.
- Some trials had methodological limitations, and independent replication is limited.
- Reviewers rated the overall quality of evidence as low to moderate.
Common colds and sinusitis
A smaller number of trials looked at colds and acute sinus infections. Some reported faster symptom improvement. The evidence here is thinner and of lower quality than for bronchitis, and reviewers have been cautious about drawing firm conclusions.
What it hasn’t shown
- Prevention. There’s no good evidence that taking pelargonium regularly keeps you from getting sick.
- Serious infections. It has not been shown to be an alternative to medical treatment for pneumonia, bacterial infections, or chronic lung conditions such as asthma or COPD.
Dosing used in research
Studied doses for adults and teenagers over 12 generally looked like this:
- Liquid extract (EPs 7630): about 30 drops, 3 times daily
- Tablets: typically 20 mg, 3 times daily
- Duration: usually started at the first signs of symptoms and continued for about 7-10 days, often a few days beyond symptom resolution. Label guidance generally advises seeing a doctor if symptoms haven’t improved within a week.
Children’s doses were lower and product-specific. Don’t give it to young children without checking with a pediatrician, and don’t use it in children under the age stated on the label (commonly 1-6 years, depending on the product and country).
Take it with a little water. The liquid form is often taken with or after meals, which may reduce stomach upset.
Safety and interactions
Pelargonium is generally well tolerated in short-term use, but there are real caveats.
Common side effects: stomach upset, diarrhea, and nausea. Occasionally rashes or other allergic reactions occur, and mild nosebleeds or gum bleeding have been reported.
Liver concerns. Regulatory reviews in Europe have looked at rare reported cases of liver injury, including hepatitis, in people taking pelargonium products. A clear causal link is hard to establish from case reports, but it’s a signal worth respecting:
- Avoid it if you have liver disease.
- Stop it and see a clinician if you develop dark urine, yellowing of the skin or eyes, upper-right abdominal pain, or unexplained fatigue.
- Be cautious combining it with other products known to stress the liver, and with high-dose green tea extract.
Bleeding risk. The root contains coumarin-type compounds. These are chemically distinct from the drug warfarin, and the practical impact at typical doses is uncertain. Still, it’s prudent to talk with your doctor before using pelargonium if you take warfarin or other anticoagulants or antiplatelet drugs, or if you have a bleeding disorder. Stop it before any planned surgery; see supplements before surgery.
Pregnancy and breastfeeding. There’s not enough safety data. Avoid.
Autoimmune conditions or immunosuppressants. Because pelargonium may affect immune signaling, discuss it with your healthcare provider first.
Seek medical care for these signs
Acute bronchitis is usually viral and resolves on its own, but a cough can also signal something more serious. See a clinician if you have:
- Shortness of breath, wheezing, or chest pain
- High fever or fever lasting more than a few days
- A cough that lasts beyond about 3 weeks
- Coughing up blood
- An underlying heart or lung condition, or if you are older or immunocompromised
How it compares to other cold-season herbs
Pelargonium’s evidence base is arguably somewhat stronger than that of many popular cold remedies, particularly for bronchitis symptoms. It’s still in the same general category of modest, uncertain, short-term benefit. For comparison, see our reviews of elderberry, where the largest trial found no benefit, and andrographis, which has its own mixed record. Our immune supplements overview puts these options side by side.
Bottom line
Pelargonium sidoides, particularly the standardized EPs 7630 extract, has more clinical trials than most herbal cold remedies. Some of them suggest it can modestly ease acute bronchitis symptoms over about a week. The evidence is limited by small, often manufacturer-funded studies, and rare reports of liver injury mean it isn’t for everyone. If you try it, use a standardized product at label doses for no more than about 10 days. Avoid it during pregnancy, while nursing, and with liver disease. Check with your doctor if you take blood thinners, and get medical care for any cough with breathing trouble, high fever, or persistence beyond a few weeks.
This article is for educational purposes only and is not medical advice. Consult a healthcare provider before starting any supplement, especially if you are pregnant, nursing, taking medication, or managing a health condition.