2-Carboxy-2-Phenylethyl 1-(4-Chlorobenzoyl)-5-Methoxy-2-Methyl-1h-Indole-3-Acetate (Tropesin, VUFB-12018) is indometacin prodrug with potent anti-inflammatory efficacy and advantageous therapeutic properties. In experiments in vivo in rats, after oral administration of a Tropesin dose of 50 mg/kg, esterolysis was observed between 2-3, with a peak level of liberated indometacin between 10-13 h after ingestion. Tropesin was administered orally to rats and dogs in the daily therapeutic dose, triple the dose and ten times the dose for 3 months. After the highest dosage, in isolated cases, some dogs were found to have superficial erosions of the gastric mucosa and dystrophic lesions of renal tubules without biochemical correlations. Indometacin, administered in parallel doses, caused severe lesions of the gastrointestinal tract with melaena and subsequent anemia, as well as severe degenerative changes in renal tubules, in all dosage groups. From the toxicological aspect, Tropesin is substantially more acceptable than indomethacin. The anti-inflammatory and anti-arthritic activities of Tropesin in comparison with indomethacin, were studied in various models of both acute and chronic inflammatory reactions. Both compounds exhibited significant therapeutic activities without substantial quantitative differences.