Aloe is a plant that makes two substances used in healthcare products. They are clear gel and yellow latex.

People mainly put aloe's clear gel on skin to treat burns, the skin condition psoriasis and even acne. Some also take the gel by mouth to treat certain conditions. Some people take aloe latex, a laxative, by mouth to treat trouble passing stool, called constipation.

Aloe gel is generally safe when used as suggested. But taking aloe latex by mouth may not be safe. In fact, taking 1 gram a day of aloe latex for a few days can cause kidney damage and might be fatal.

Research on the use of aloe for certain conditions shows:

• Burns and wounds. Putting aloe gel on first- and second-degree burns and wounds may speed healing. There's not enough proof to know if aloe gel helps sunburns heal.
• Acne. Research suggests that using aloe gel with the prescription acne medicine tretinoin (Retin-A, Atralin, others) might work better than the acne medicine alone. You put the gel and the medicine on your skin.
• Psoriasis. Aloe extract cream might ease symptoms of mild to moderate psoriasis. You might need to use the cream several times a day for a month or more to see your skin get better.
• Herpes simplex virus. Putting a cream that has aloe extract on the skin might help sores heal sooner.
• Oral lichen planus. This ongoing condition may cause irritated swollen tissues inside the mouth. Research suggests that putting aloe gel on the sores for eight weeks might help ease the symptoms.
• Constipation. It's not clear whether taking aloe latex by mouth treats trouble passing stool, called constipation. Aloe latex acts as a laxative. But aloe latex also may cause stomach cramps and loose stools.

Experts believe aloe gel is safe when put on the skin using directions. It might be safe to take small doses by mouth for a short time.

Taking aloe latex or whole-leaf extract by mouth may be unsafe. It's likely unsafe in high doses. Taking 1 gram a day of aloe latex for a few days can cause short-term kidney failure. It can be fatal.

Aloe latex also might cause cancer. Other side effects include stomach cramps and loose stools. Children younger than age 12 should not take aloe latex and whole-leaf extract by mouth.

People who are pregnant or breastfeeding should not use aloe in either form.

Mixing aloe with the following medicines may cause harm:

• Anticoagulants and antiplatelet medicines, herbs and supplements. These types of medicines, herbs and supplements slow blood clotting. Taking aloe by mouth also might slow blood clotting. Taking aloe by mouth with these types of medicines might lead to more bleeding.
• Digoxin (Lanoxin). Taking aloe latex by mouth can lower potassium levels. Low potassium might raise the side effects of digoxin. Don't take aloe latex and digoxin together.
• Diabetes medicines. Taking aloe gel by mouth while taking diabetes medicines might raise the risk of low blood sugar, called hypoglycemia.
• Other medicines taken by mouth. Taking aloe latex by mouth can keep the body from taking in other medicines. This might lower how well those medicines work.
• Sevoflurane (Sojourn, Ultane). This medicine used to cause a sleeplike state during surgery, called anesthesia, may slow blood clotting. Taking aloe by mouth also may slow blood clotting. Taken together, they might cause too much bleeding during surgery.
• Stimulant laxatives. Taking aloe latex with medicines that help move stool through the body might make the bowels work too hard. This can lead to loss of fluids, called dehydration.
• Warfarin (Jantoven). Taking aloe latex by mouth can cause loose stools. This can add to the effects of warfarin, a blood-thinning medicine. This can raise the risk of bleeding.
• Water pills, also called diuretics. Taking aloe latex by mouth with diuretics might lower the body's potassium levels too much, leading to a condition called hypokalemia.