When inhaled, trichloroethylene produces central nervous system depression resulting in general anesthesia. These effects may be mediated by trichloroethylene acting as a positive allosteric modulator of inhibitory GABA and glycine receptors. Its high blood solubility results in a less desirable slower induction of anesthesia. At low concentrations, it is relatively non-irritating to the respiratory tract. Higher concentrations result in tachypnea. Many types of cardiac arrhythmias can occur and are exacerbated by epinephrine (adrenaline). It was noted in the 1940s that TCE reacted with carbon dioxide (CO) absorbing systems (soda lime) to produce dichloroacetylene by dehydrochlorination and phosgene. Cranial nerve dysfunction (especially the fifth cranial nerve) was common when TCE anesthesia was given using CO absorbing systems. ] Muscle relaxation with TCE anesthesia sufficient for surgery was poor. For these reasons as well as problems with hepatotoxicity, TCE lost popularity in North America and Europe to more potent anesthetics such as halothane by the 1960s.
The symptoms of acute non-medical exposure are similar to those of alcohol intoxication, beginning with headache, dizziness, and confusion and progressing with increasing exposure to unconsciousness. Much of what is known about the chronic human health effects of trichloroethylene is based on occupational exposures. Besides the effects to the central nervous system, workplace exposure to trichloroethylene has been associated with toxic effects in the liver and kidney. A history of long-term exposure to high concentrations of trichloroethylene is a suspected environmental risk of Parkinson's disease.