Contact of liquid DMS with the eyes rapidly causes severe irritation of the eyes and eyelids. Unless the liquid is quickly removed by thorough irrigation with water, prolonged or permanent eye damage may result.
Contact of liquid DMS with the skin produces initial reddening and possibly itching, followed by severe burns that may extend through the skin to the underlying tissues if the liquid is not rapidly removed. These burns may heal slowly. In lower concentrations, the corrosive action on the skin is accompanied by prolonged analgesia. Dimethyl sulfate may be absorbed through the skin, and absorption of large quantities may produce pulmonary effects, circulatory collapse, convulsions, and unconsciousness. The effects of dilute solutions may not appear for several hours.
When swallowed, DMS causes severe irritation and damage to the esophagus and stomach. However, signs of injury to the digestive tract may be suppressed because of the analgesic action of dimethyl sulfate. The most prominent symptoms following ingestion are respiratory tract effects.