Malaoxon is a chemical compound with the formula C₁₀H₁₉O₇PS. More specifically, it is a phosphorothioate. It is a breakdown product of, and more toxic than, malathion.

This chemical may be sensitive to prolonged exposure to air. (NTP, 1992). Slightly water soluble.

This chemical is probably combustible. (NTP, 1992)

Symptoms of exposure to this type of compound include cholinesterase inhibition, miosis, frontal headache, increased bronchial secretion, nausea, vomiting, sweating, abdominal cramps, diarrhea, lacrimation, increased salivation, bradycardia, cyanosis and muscular twitching of the eyelids, tongue, face and neck, possibly progressing to convulsions. Other symptoms include hyperemia of the conjunctiva, dimness of vision, rhinorrhea, bronchoconstriction, cough, fasciculation, anorexia, incontinence, eye changes, weakness, dyspnea, bronchospasm, hypotension or hypertension due to asphyxia, restlessness, anxiety, dizziness, drowsiness, tremor, ataxia, depression, confusion, neuropathy (rare), coma and death from depression of respiratory or cardiovascular systems. Exposure to this type of compound may result in giddiness, nervousness, blurred vision, discomfort (tightness) in chest, papilledema, muscular weakness, loss of reflexes, loss of sphincter control, cardiac arrhythmias, various degrees of heart block and cardiac arrest. It may also result in spasm of accommodation, aching pain in and about the eye, nystagmus, delayed distal axonopathy and parethesias and paralysis of limbs. A decrease in blood pressure may occur. Respiratory failure may also occur.