Research on dual inhibitors of both 5-LOX and COXs gained interest due to the overexpressions of these enzymes during the malignant state of the evolution of prostate cancer. In order to take part in this research, new N-aroyl-tetrahydro-gamma-carbolines issued from the modification of Indomethacin have been synthesised. As for the NSAIDs, the compounds have been tested for their activity against COX(1), COX(2) plus against 5-LOX and against the proliferation of malignant prostate cancer. Interesting cytotoxic activities and selectivities of some tetrahydro-gamma-carboline derivatives have been obtained.