[8] Oral ingestion of aloe vera extracts may cause acute abdominal pain and cramps, and hepatitis if consumed chronically.

[5][9] The genus name Aloe is derived from the Arabic word alloeh, meaning "bitter and shiny substance" or from Hebrew אוהלים ahalim, plural of אוהל ahal.

[4] The leaves are thick and fleshy, green to grey-green, with some varieties showing white flecks on their upper and lower stem surfaces.

[30] Aloe vera is considered to be native only to the south-east[31] Arabian Peninsula in the Hajar Mountains in north-eastern Oman and eastern U.A.E.

[44] There is large-scale agricultural production of Aloe vera in Australia,[46] Cuba, the Dominican Republic, China, Mexico,[47] India,[48] Jamaica,[49] Kenya, Tanzania, South Africa,[50] Spain,[51] and the United States,[52] with much of the output going toward the cosmetics industry.

[5] For people with allergies to Aloe vera, skin reactions may include contact dermatitis with mild redness and itching, difficulty with breathing, or swelling of the face, lips, tongue, or throat.

[5][11][15] Aloin, a compound found in the semi-liquid latex of some Aloe species, was a common ingredient in over-the-counter (OTC) laxative products in the United States until 2002 when the Food and Drug Administration banned it because manufacturers failed to provide the necessary safety data.

[5][9][55] Aloe vera has potential toxicity, with side effects occurring at some dose levels both when ingested and when applied topically.

[5][15] Although toxicity may be less when aloin is removed by processing, Aloe vera ingested in high amounts may induce side effects, such as abdominal pain, diarrhea or hepatitis.

[5][56] Chronic ingestion of aloe (dose of 1 gram per day) may cause adverse effects, including hematuria, weight loss, and cardiac or kidney disorders.

[5] Aloe vera juice is marketed to support the health of the digestive system, but there is neither scientific evidence nor regulatory approval for this claim.

Cosmetic companies commonly add sap or other derivatives from Aloe vera to products such as makeup, tissues, moisturizers, soaps, sunscreens, incense, shaving cream, or shampoos.

[28] Orally ingested non-decolorized aloe vera leaf extract was listed by the California Office of Environmental Health Hazard Assessment among "chemicals known to the state to cause cancer or reproductive toxicity",[57] possibly resulting from the anthraquinones.

[11] Since 2016, aloe vera whole leaf extract is classified as a possible human carcinogen (group 2B) by the International Agency for Research on Cancer.

[9] Oral ingestion of aloe vera is potentially toxic,[5][11] and may cause abdominal cramps and diarrhea which in turn can decrease the absorption of drugs.

[5][9] Ingested aloe products may have adverse interactions with prescription drugs, such as those used to treat blood clots, diabetes, heart disease and potassium-lowering agents (such as Digoxin), and diuretics, among others.