Blue-green algae, which is most often found in stagnant, slow-moving water when temperatures are high, can poison sheep. Symptoms generally develop quite rapidly and may resemble an allergic reaction. Convulsions may occur, but more frequently the sheep sinks to the ground and dies without struggling. Smaller amounts of poison cause weakness and staggering, followed by recovery. In some instances, apparent recovery from an attack is followed in a few days or weeks by evidence of photosensitization. There may be inflammation of the muzzle, the skin of the ear, the udder, or other parts of the body. Jaundice is often seen, and constipation is a common symptom. Such cases usually recover under good care.