Coturnism is an illness featuring muscle tenderness and rhabdomyolysis (muscle cell breakdown) after consuming quail (usually common quail, "Coturnix coturnix", from which the name derives) that have fed on poisonous plants.

From case histories it is known that the toxin is stable as four-month-old pickled quail have been poisonous. Humans vary in their susceptibility; only one in four people who consumed quail soup containing the toxin fell ill. The toxin is apparently fat-soluble as potatoes fried in quail fat have proved poisonous.

Coniine from hemlock consumed by quail has been suggested as the cause, though quail resist eating hemlock. Hellebore has also been suggested as the source of the toxin. It has also been asserted that this evidence points to the seeds of the annual woundwort ("Stachys annua") being the causal agent. It has been suggested that "Galeopsis ladanum" seeds are not responsible.

The symptoms of rhabdomyolysis depend on its severity and whether kidney failure develops. Milder forms may not cause any muscle symptoms, and the diagnosis is based on abnormal blood tests in the context of other problems. More severe rhabdomyolysis is characterized by muscle pain, tenderness, weakness and swelling of the affected muscles. If the swelling is very rapid, as may happen after someone is released from under a collapsed building, the movement of fluid from the bloodstream into damaged muscle may cause low blood pressure and shock. Other symptoms are nonspecific and result either from the consequences of muscle tissue breakdown or from the condition that originally led to the muscle breakdown. Release of the components of muscle tissue into the bloodstream causes electrolyte disturbances, which can lead to nausea, vomiting, confusion, coma or abnormal heart rate and rhythm. The urine may be dark, often described as "tea-colored", due to the presence of myoglobin. Damage to the kidneys may give rise to decreased or absent urine production, usually 12 to 24 hours after the initial muscle damage.

Swelling of damaged muscle occasionally leads to compartment syndrome—compression of surrounding tissues, such as nerves and blood vessels, in the same fascial compartment—leading to the loss of blood supply and damage or loss of function in the part(s) of the body supplied by these structures. Symptoms of this complication include pain or reduced sensation in the affected limb. A second recognized complication is disseminated intravascular coagulation (DIC), a severe disruption in blood clotting that may lead to uncontrollable bleeding.

The prognosis depends on the underlying cause and whether any complications occur. Rhabdomyolysis complicated by acute kidney impairment in patients with traumatic injury may have a mortality rate of 20%. Admission to the intensive care unit is associated with a mortality of 22% in the absence of acute kidney injury, and 59% if kidney impairment occurs. Most people who have sustained kidney impairment due to rhabdomyolysis fully recover their kidney function.