As the use of medicinal plants increases, screening of their toxicity is crucial to guarantee the safety of the users. Hexane and acetone extracts of three South African plants, traditionally used for the management of opportunistic fungal infections in human immune deficiency virus/acquired immune deficiency syndrome (HIV/AIDS) patients were assayed for toxicity to hatching and larval mortality of Artemia salina. Lowest percentage values of hatching success were observed in cysts incubated with hexane and acetone extracts of Arctotis arctotoides, respectively and were significantly lower (P < 0.05) than that of the positive control (amphotericin B). Based on Meyer's toxicity index, both extracts of Pittosporum viridiflorum and the acetone extract of A. arctotoides with LC 50 values > 1 mg/ml were considered as non-toxic and may be further explored for development of plant-based pharmaceuticals. The hexane and acetone extracts of A. arctotoides and the hexane extract of Gasteria bicolor with LC 50 values < 1 mg/ml have shown significant biological activity, indicative of the presence of potent cytotoxic components which warrant further investigation. The in vivo lethality of A. salina has been used as a convenient toxicological screening system, while the resistance to harmful effects by Artemia cysts made the hatchability assay less desirable than the lethality test.