Background

Coleus (Plectranthus barbatus) is a plant in the mint family. It grows in tropical regions of Asia and is used in traditional Ayurvedic medicine.

Coleus root and stem contain a chemical called forskolin. Forskolin has effects that might widen blood vessels and lower blood pressure.

People use coleus for chest pain, asthma, eczema, heart failure, high blood pressure, obesity, and many other conditions, but there is no good scientific evidence to support these uses.

Don't confuse coleus with Perilla. These are not the same.

Safety Safety definitions

When taken by mouth: Coleus extract is possibly safe when used in doses of 500 mg or less daily for up to 3 months. But it is possibly unsafe when used in larger doses. Larger doses might cause side effects including diarrhea, constipation, and vomiting.

When inhaled: Coleus is possibly safe when used as a single dose of forskolin powder. Side effects might include throat irritation, cough, tremor, and restlessness.

When applied into the eye: Coleus is possibly safe when used in eye drops. Side effects might include stinging eyes.

Special Precautions & Warnings:

Pregnancy: Coleus is possibly unsafe when taken by mouth during pregnancy. Coleus might slow or stop the growth of the fetus. Avoid use.

Breast-feeding: There isn't enough reliable information to know if coleus is safe to use when breast-feeding. Stay on the safe side and avoid use.

Bleeding disorders: Coleus contains a chemical called forskolin, which might increase the risk of bleeding in some people.

Heart disease: Coleus contains a chemical called forskolin, which might lower blood pressure. Coleus might interfere with treatments for heart conditions and could make these conditions worse.

Low blood pressure: Coleus contains a chemical called forskolin, which might lower blood pressure. If your blood pressure is already low, taking coleus might make it drop too much.

Surgery: Coleus contains a chemical called forskolin, which might increase bleeding during and after surgery. Stop using coleus at least 2 weeks before a scheduled surgery.

Effectiveness

Dosing & administration

There isn't enough reliable information to know what an appropriate dose of coleus might be. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult a healthcare professional before using.

Interactions with pharmaceuticals

Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)

Interaction Rating=Moderate Be cautious with this combination.

Some medications are changed and broken down by the liver. Coleus might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)

Interaction Rating=Moderate Be cautious with this combination.

Some medications are changed and broken down by the liver. Coleus might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications for high blood pressure (Antihypertensive drugs)

Interaction Rating=Moderate Be cautious with this combination.

Coleus might lower blood pressure. Taking coleus along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure closely.

Medications for high blood pressure (Calcium channel blockers)

Interaction Rating=Major Do not take this combination.

Coleus might decrease blood pressure. Calcium channel blockers are a type of medicine used to decrease blood pressure. Taking coleus with calcium channel blockers might cause your blood pressure to go too low.

Medications that increase blood flow to the heart (Nitrates)

Interaction Rating=Major Do not take this combination.

Coleus increases blood flow. Taking coleus with medications that increase blood flow to the heart might increase the chance of dizziness and lightheadedness. Don't use coleus if you are taking medications that increase blood flow to the heart.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating=Moderate Be cautious with this combination.

Coleus might slow blood clotting. Taking coleus along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Warfarin (Coumadin)

Interaction Rating=Moderate Be cautious with this combination.

Coleus might change how your body breaks down warfarin. Be watchful of this combination and talk to your health provider.

Interactions with herbs & supplements

Herbs and supplements that might lower blood pressure: Coleus might lower blood pressure. Taking it with other supplements that have the same effect might cause blood pressure to drop too much. Examples of supplements with this effect include andrographis, casein peptides, L-arginine, niacin, and stinging nettle.
Herbs and supplements that might slow blood clotting: Coleus might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.

Interactions with foods

There are no known interactions with foods.