Background Consumption of herbal medicines among people living with HIV is a common practice in Sub-Saharan Africa. The utilization of herbal medicines was at 17.5% and 67.9% in Malawi and Nigeria, respectively. There is inadequate data on use and adverse reactions (ADRs) reporting of herbal medicines among people living with HIV (PLWHIV). This study was designed to investigate use and ADRs reporting of herbal medicines among PLWHIV at the University Teaching Hospitals in Blantyre, Malawi and Ibadan, Nigeria.MethodologyA cross-sectional study was conducted among PLWHIV attending Antiretroviral Therapy (ART) clinic at Queen Elizabeth Central Hospital, Blantyre, Malawi and University College Hospital, Ibadan, Nigeria. A structured questionnaire was administered to 360 and 370 participants in Blantyre and Ibadan respectively, through face-to-face interviews after obtaining their informed consent. Results The prevalence of herbal medicines use among PLWHIV in Malawi and Nigeria was at 80.6% and 55.7% (p<0.001), respectively. The most frequently used herbal medicines in Malawi were Aloe vera (14.0%), Moringa oleifera (14.0%), Zingiber officinale (13.0%) and Allium sativum (7.0%). Likewise, in Nigeria, the most commonly used herbal medicines were Zingiber officinale (15.0%), Vernonia amygdalina (14.0%), Moringa oleifera (9.0%), and Allium sativum (11.0%). The major reason for herbal medicines’ use in Malawi was ready availability (42.1%) and perception that it boosts immunity (44.6%) in Nigeria. The PLWHIV reported experiencing suspected herbal medicine ADRs in Malawi (3.9%) and in Nigeria (8.0%).Conclusion A higher percentage of people living with HIV are using herbal medicines in Malawi as well as in Nigeria. In both countries, a few participants reported experiencing suspected ADRs related to herbal medicines.