 [ Symptoms ] what should i do if i suspect an overdose of malathion [ Disease ] this medication may be harmful if swallowed if swallowing or overdose is suspected contact your local poison control center or emergency room immediately us residents can call the us national poison hotline at 1 800 222 1222 canada residents can call a provincial poison control center symptoms of overdose may include breathing problems muscle weaknessparalysis shaking increased sweatingsalivatears increased urine nausea vomiting diarrhea anxiety headache confusion dizziness drowsiness slow or fast heartbeat