Since succinyl choline was introduced, into clinical anesthesia, it has been used as main muscle relaxant because of its rare side effects and short duration of action. Our interest in the effects of this drug on extraocular muscles and intraocular pressure began in 1957 following reports of vitreous expulsion in patients who received succinylcholine during ocular surgery. The effects of muscle relaxants on the intraocular pressure were studied in 60 healthy human subjects. When succinylcholine was given alone, 20 human subjects had a mean increase in intraocular pressure of 10. 5 mmHg. When gallamine 2. 5 mg/kg or pancuronium 80 µg/kg was used, 20 subjects showed a mean decrease of 3. 1 mm Hg from control. Giving gallamine (20 mg) or dtubo curarine(3 mg) 2-3 minutes prior to the administration of succinylcholine, 20 human subjects had no significant change in intraocular pressure. This simple method prevents the increase in intraocular pressure associated with the use of succinylcholine.