This fungus has been cited as being responsible for 10% of all mushroom poisonings in Europe. For example, 70 people required hospital treatment in Geneva alone in 1983, and the fungus accounted for 33 of 145 cases of mushroom poisoning in a five-year period at a single hospital in Parma. Poisoning is said to be mainly gastrointestinal in nature; symptoms of diarrhoea, vomiting and headache occur 30 minutes to 2 hours after consumption and last for up to 48 hours. Acute liver toxicity and psychiatric symptoms like mood disturbance or delirium may occur. Rarely, symptoms of depression may last for months. At least one source reports there have been fatalities in adults and children. Hospital treatment of poisoning by this mushroom is usually supportive; antispasmodic medicines may lessen colicky abdominal cramps and activated charcoal may be administered early on to bind residual toxin. Intravenous fluids may be required if dehydration has been extensive, especially with children and the elderly. Metoclopramide may be used in cases of recurrent vomiting once gastric contents are emptied. The identity of the toxin(s) is unknown, but chemical analysis has established that there are alkaloids present in the mushroom.

A study of trace elements in mushrooms in the eastern Black Sea Region of Turkey found E. sinuatum to have the highest levels of copper (64.8 ± 5.9 μg/g dried material—insufficient to be toxic) and zinc (198 μg/g) recorded. Caps and stalks tested in an area with high levels of mercury in southeastern Poland showed it to bioaccumulate much higher levels of mercury than other fungi. The element was also found in high levels in the humus-rich substrate. Entoloma sinuatum also accumulates arsenic-containing compounds. Of the roughly 40 μg of arsenic present per gram of fresh mushroom tissue, about 8% was arsenite and the other 92% was arsenate.