Educational information, not medical advice — ask your doctor or midwife.
Hombre grande is the bitter wood and bark of Quassia amara, a small tropical tree. In the Dominican Republic and the Eastern Caribbean it is often called amargo, which simply means bitter. The wood is soaked in water or rum to make a sharp bitter drink.
People take it mainly as a digestive bitter, for poor appetite and for intestinal worms. It is also used on the scalp as a rinse for head lice.
Here is the honest verdict. Human evidence is thin. One small trial supports a quassia lotion for head lice.
The other uses rest on tradition, lab tests and animal work. Long use in a tradition is not proof that something works. It is also not proof that it is safe.
The bitter taste is the part with the clearest logic. Bitter plants make your mouth water and appear to raise stomach juices. That is the old bitters idea behind taking it before meals.
In test tubes and in animals, quassinoids from the wood slow malaria parasites and some worms. These effects have not been shown to carry over to people.
In laboratory tests, quassia extract kills head lice. A small trial of a quassia lotion on children's scalps backed this up.
In animal studies, high doses of quassin lowered sperm counts in male rats. Whether this happens in men is not known. It is still a good reason to be careful.
The classic Caribbean form is a bottle of bark or wood chips steeped in water or rum.
Shop forms include tincture drops, bottled bitter tonics, dried chips for tea, and capsules.
Some mixed bitters blends list quassia among several bitter herbs. Check the label, because the amount is often small.
For head lice, it is used as a scalp lotion or hair rinse. That form is not swallowed.
Quassia is also sold as a garden and pet insect spray. Those products are not made for people. Never drink one.
Hombre grande has been used across the Caribbean and northern South America for centuries.
The name quassia honours Graman Quassi. He was an enslaved healer in Suriname. In the 1700s he showed Europeans how the bitter wood was used.
In Dominican and Eastern Caribbean homes, amargo was taken for weak appetite, upset stomach and worms. It was also drunk during fevers and rinsed through the hair for lice.
European pharmacy later listed quassia wood as a bitter tonic and as a fly poison. Cups carved from the wood were sold so that water left in them turned bitter.
Stop and see a doctor if you vomit again and again, or have strong stomach pain.
Get urgent care for black or bloody stools, vomit that looks like coffee grounds, or new easy bruising.
Get emergency care for chest pain, fainting, or a heartbeat that feels very slow or irregular.
Get emergency care for swelling of the lips or face, a spreading rash, or trouble breathing.
Tell your doctor if you took it while pregnant or while on a blood thinner.
In the United States quassia is sold as a dietary supplement and as a flavouring in small amounts. In the UK and EU it is sold as a food bitter and a herbal product. No country approves it as a medicine to treat a disease.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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