From a methanol extract of Artemisia caruifolia, which showed a moderate inhibitory activity on HIV-1 protease in a preliminary screening, N¹, N⁵, N¹⁰-tri-p-coumaroylspermidine and three dicaffeoylquinic acids were isolated. The former compound was found to appreciably inhibit HIV-1 protease. Of related amides which were chemically synthesized, N¹, N⁵, N¹⁰, N¹⁴-tetra-p-coumaroylspermine and N¹, N⁴, N⁷, N¹⁰, N¹³-penta-p-coumaroyltetraethylenepentamine inhibited HIV-1 protease more potently than N¹, N⁵, N¹⁰-tri-p-coumaroylspermidine.