Provided is an FTD- and TPI-containing oral pharmaceutical composition which can be orally administered and is stable even under high humidity conditions. This oral pharmaceutical composition contains α,α,α-trifluorothymidine and 5-chloro-6-(2-iminopyrrolidine-1-yl) methyl-2,4 (1H, 3H)-pyrimidine dione hydrochloride as the active ingredient, and contains, as an excipient, an additive having an 85% or greater critical relative humidity at 25°C.
