Ph.D. (Botany) / The most well-known tonic plants in South Africa have been used traditionally for the treatment of a great variety of ailments but aspects of their ethnobotany and chemistry remain poorly studied. Possible relationships between their ethnobotany and pharmacology are mostly speculative. In this study, literature reviews of the ethnobotany of these plants were combined with phytochemical screening studies and bitterness taste testing results in order to establish constituent patterns which may contribute to a scientific rationale for the claimed tonic (stimulating) properties of these plants. The tonic concept and definitions of terms associated with it are often used incorrectly and ambiguously. An analysis of literature on the traditional healing systems across the globe was used to establish the historical and cultural aspects relevant to tonics. This analysis revealed that sickness/illness is usually considered to be a result of imbalance in many cultures, whether this imbalance is between the patient and the environment or due to a lack of homeostasis in the body. In several healing cultures substances or mixtures of substances are used to rectify these imbalances through proposed effects on several bodily systems concurrently. According to some cultures, as in Eastern and Indian traditional medicine, tonic plants are considered superior to other medicinal plants in that they impart health, strength and a general sense of well-being, as well as being prophylactic. This definition of a tonic plant is consequently broad, but excludes plants merely used as multipurpose medicines. Where these tonics exhibit a specific mode of action, further classification is required, i.e. as bitter, adaptogenic, alterative, adjuvant or stimulant tonics. The South African traditional tonic plants studied were Agathosma species (Rutaceae), Aloe species (Asphodelaceae), Arctopus species (Apiaceae), Artemisia afra (Asteraceae), Balanites maughamii (Balanitacae), Dicoma species (Asteraceae), Harpagophytum procumbens (Pedaliaceae), Hypoxis hemerocallidea (Hypoxidaceae), Muraltia heisteria (Polygalaceae), Sutherlandia species (Fabaceae), Vernonia oligocephala (Asteraceae), Warburgia salutaris (Canellaceae), Withania somnifera (Solanaceae) and Ziziphus mucronata (Rhamnaceae). A detailed compendium of medicinal applications was compiled following a thorough, in-depth scrutiny of the historical and medicinal ethnobotany of each of these species. Such ethnobotanical data is important in understanding the cultural aspects of healing in southern Africa, and provides valuable direction and focus with regards to the phytochemical and pharmacological research of these plants.