A randomised double blind trial of 2-(2-Hydroxy-4-methylphenyl) Aminothiazole Hydrochloride 0.1% (CBS 113A) versus placebo was carried out in 43 eyes with episcleritis. Our results show that CBS 113A is effective in reducing the signs of conjunctival and episcleral inflammation in mild episcleritis within the first week of administration of the drug (Day 3: Total Score p = 0.0013, Conjunctival Injection p = 0.017, Episcleral Injection p = 0.0018 and Day 7: Total Score p = 0.01, Conjunctival Injection p = 0.014, Episcleral Injection p = 0.027). CBS 113A was not effective against severe episcleritis. No significant side effects were found apart from a stinging sensation. There was no effect on intraocular pressure. The potential use of this new drug is discussed.