What is Simarouba?

Simarouba glauca is a fast-growing tropical tree found across Central America, the Caribbean, parts of South America, and increasingly cultivated in India and Southeast Asia. Nearly every part of the tree — bark, leaves, roots, and seeds — has been used in traditional medicine, while its oil-rich seeds have drawn modern interest as a biofuel and edible oil source. It belongs to the Simaroubaceae family, a group well known for producing bitter compounds called quassinoids with documented biological activity.

How does Simarouba work?

The tree's most studied compounds are quassinoids — intensely bitter plant chemicals that disrupt the energy production and reproduction of parasites, harmful bacteria, and certain cancer cells. The seed oil is rich in oleic and lauric acids, which support healthy lipid profiles and have antimicrobial properties. Tannins and flavonoids in the leaves and bark add antioxidant and anti-inflammatory effects that help calm gut inflammation and support immune response.

What forms does Simarouba come in?

Bark decoctions and tinctures are the most traditional forms for antiparasitic and fever-reducing use. Leaf extracts are used topically and internally for skin conditions and digestion. The cold-pressed seed oil can be used culinarily or applied to skin. Standardized capsules and powders are increasingly available, though quality and standardization vary widely.

Where it comes from:

Indigenous peoples of Central America and the Amazon have used Simarouba bark for centuries to treat malaria-like fevers, intestinal parasites, and digestive ailments. In India, it gained attention in the 20th century as a drought-resistant tree with dual value as a medicinal plant and biofuel crop, leading to significant Indian government interest in its cultivation. It also appears in traditional Brazilian and Caribbean herbal medicine under the name 'aceituno' or 'marupá'.

What does Simarouba help with?

• Intestinal parasites and worms: Simarouba bark contains quassinoids that are toxic to intestinal parasites and protozoa, disrupting their ability to produce energy and reproduce. This is its most historically documented use across multiple traditional medicine systems and has the strongest supporting laboratory and early clinical investigation.
• Digestive issues and stomach upset: The bark and leaf preparations have been used to calm cramping, bloating, and diarrhea associated with gut infections. Tannins in the plant help tone the gut lining and reduce excessive fluid secretion, which may ease loose stools and irritation.
• Fever and malaria-like infections: Simarouba has a centuries-long history as a fever remedy in Central and South America, and quassinoids like glaucarubinone have shown activity against the malaria parasite in laboratory studies. Traditional healers used bark decoctions specifically when fevers were accompanied by chills and digestive symptoms.
• Bacterial and fungal infections: Extracts from the leaves and bark have demonstrated activity against a range of bacteria and fungi in laboratory settings, including some resistant strains. The lauric acid in seed oil also contributes natural antimicrobial action.
• Amoebic dysentery: Traditional use specifically calls out Simarouba bark decoctions for dysentery caused by amoeba. Quassinoids are thought to act directly against Entamoeba histolytica, the organism responsible, though formal human trials are limited.
• Skin infections and wounds: Leaf poultices and seed oil are used topically in traditional practice for infected wounds, skin fungus, and inflammatory skin conditions. The combination of antimicrobial compounds and omega-rich oil supports both infection control and skin healing.
• Inflammation and pain: Flavonoids and quassinoids in Simarouba extracts have shown anti-inflammatory activity in preclinical research, helping to reduce inflammatory signaling. Traditional preparations are used for joint pain and inflammatory conditions in South American herbalism.
• High cholesterol (seed oil): The cold-pressed seed oil has a fatty acid profile comparable to olive oil, with high oleic acid content linked to supporting healthy cholesterol levels and cardiovascular function. It is gaining attention as an edible oil alternative in food systems research.

What can Simarouba help prevent?

• Recurrence of intestinal parasite infection (as part of a cleansing protocol in traditional use)
• Skin and wound infection (topical seed oil application)

Which foods are rich in Simarouba?

Simarouba is not found in common foods — its active quassinoids are specific to the tree and not present in any typical dietary source. However, to support the same goals (antiparasitic gut health, immune defense, and anti-inflammatory balance), emphasize: 1) Garlic — a well-documented natural antiparasitic and antimicrobial food; 2) Pumpkin seeds — traditionally used across cultures to expel intestinal worms; 3) Papaya seeds — contain compounds like carpaine with antiparasitic properties; 4) Coconut oil — high in lauric acid, similar to Simarouba seed oil, with antimicrobial activity; 5) Turmeric — supports gut lining integrity and reduces infection-driven inflammation. Avoid high-sugar foods and refined carbohydrates when dealing with gut parasites or infections, as sugar feeds pathogenic organisms.

What are the side effects of Simarouba?

• Nausea and vomiting (especially with higher bark doses)
• Stomach cramping or diarrhea
• Mild headache
• Skin irritation (topical use, rare)
• Not recommended in pregnancy: may stimulate uterine activity (traditional caution)
• Bitterness and throat irritation with decoctions

Good to know:

Simarouba is generally considered safe at doses used in traditional medicine, but higher doses — particularly of bark extracts — can be irritating to the gastrointestinal tract. Quassinoids are potent compounds and should not be taken in excess. Pregnant and breastfeeding women should avoid therapeutic doses. Long-term safety data in humans is limited.

How much Simarouba should you take?

• Recommended daily: Bark decoction: 1–2 cups of tea daily (5–10g dried bark per 500ml water); standardized extract capsules: 300–500mg once or twice daily; seed oil (culinary/topical): 1–2 tablespoons daily or as needed topically. Doses vary significantly by preparation — follow product-specific guidance.
• Best time of day: Bark decoctions and extracts are traditionally taken in the morning on an empty stomach for antiparasitic use; seed oil can be used at any meal.
• With or without food: Bark extracts are best tolerated with a small amount of food to reduce stomach irritation; seed oil is used with or as part of meals.
• Time to effect: Antiparasitic and digestive effects: 3–14 days for noticeable change; anti-inflammatory or cholesterol-related benefits from seed oil: 4–8 weeks of consistent use.
• How long to take it: For parasite cleansing: typically 2–4 weeks, then a break of equal duration. For ongoing digestive or anti-inflammatory support: cycle 6–8 weeks on, 2–4 weeks off. Do not use high-dose bark preparations continuously for extended periods without professional guidance.