The principle side effects reported are excessive stimulation and high blood pressure. Yerba mate has not been proven to enable weight loss. Some case reports of poisoning (leading to hospitalization) with this agent have been reported, and excessive use has been linked to esophageal cancer.

Guar Gum

Also known as guar, guar flour, and jaguar gum, guar gum is a dietary fiber obtained from the Indian cluster bean. Guar gum has been used extensively as a thickening agent for foods and pharmaceuticals. It has been studied for decreasing cholesterol, management of diabetes, and weight loss. As a weight loss product, it has been used to promote normal gastrointestinal motility and maintain fecal bulk. It has been noted to decrease appetite by providing a "feeling of fullness." However, like glucomannan, guar gum and guar gum preparations have been implicated in esophageal obstruction. The water-retaining capacity of the gum permits it to swell to 10- to 20-fold and has led to gastrointestinal obstructions. Guar gum has also been known to cause significant fluctuations in blood glucose (sugar) levels, thus diabetic patients should not use these preparations.

Guarana

 Made from the seeds of a plant native to Brazil, guarana is an effective central nervous system stimulant. It is used as a weight loss product due to its stimulant and diuretic effect. Guarana contains 2½ to five percent caffeine and may cause high blood pressure. Some of the extracts have been known to inhibit platelet aggregation—known to prolong bleeding and interact with anticoagulants (i.e., warfarin [Coumadin]). Many advertisements state that guarana is free from side effects; however, this statement is not true. Side effects from guarana may include nausea, dizziness, and anxiousness.

Aloe

 Most often used as a topical product for wound healing, oral forms of aloe are added to herbal weight-loss products. Oral aloe produces a strong cathartic response (producing bowel movements), and many aloe weight-loss products are marketed as "internal cleansers." However, aloe or aloe-containing products should not be ingested orally. Use of this agent orally has lead to side effects such as abdominal cramping, diarrhea, electrolyte disturbances, and decreases in potassium. In addition, due to the side effects, significant drug interactions can occur with some medications, including digoxin (Lanoxin). The use of aloe internally has not been shown to be effective for permanent weight loss.

Cascara

Cascara is a common ingredient used in weight loss products. One of the few herbs approved as an over-the-counter drug by the FDA, it is a strong stimulant laxative. Misuse of this herb has caused disturbances in electrolytes (such as potassium and sodium). It should not be taken if you are pregnant or lactating (can be passed to milk). Cascara may interact with medications such as digoxin and diuretics.