A number of species of the genus Phyllanthus (Euphorbiaceae) have been tested for their efficacy as antivirals, partly on the basis of references to traditional usage for the treatment of diseases possibly having a viral origin. There are also many references to indigenous uses and to laboratory assays for other biological activities in this large genus (550+ species). These citations have been arranged by subgenus, section, subsection and species and have been published in three previous papers. This paper summarizes selected clustering of usage and effect by subgeneric taxa. Consideration of the data from ethnobotany, in vitro assays and clinical trials supported the presence of some type of biological activity(s) particularly within the subgenus Phyllanthus. Although the herbaceous species of subgenus Phyllanthus have been extensively used to treat jaundice, and have generally inhibited hepadnavirus DNAp, effects on chronic infection with hepatitis B virus (HBV) or related viruses have generally been negative. Alternative explanations for the wide usage have been little explored. Other medical categories suggested possible leads for research, or possibly, herbal or galenic remedies with bona fide effects. In most cases, the data remain suggestive but not conclusive.