Confirmation of identity, along with determination of the quality and purity of herbal drug is an important step towards ensuring its safety and efficacy. This study therefore sought to document the botanical constituents and drug indications of traditional oral liquid herbal formulations (TOLHFs) manufactured in Ogbomoso, Nigeria. It also examined the conservation status of the medicinal plants so used alongside the cultivation efforts being made by the drug manufacturers in order to provide information on whether continual exploitation of the plants for TOLHFs is sustainable. Through a questionnaire, 14 traditional herbal medical practitioners (THMPs) provided information on the recipes of their products, the sources of their raw material herbs, and types of health conditions treated or managed with the drugs. Sustainability potential of the drugs was quantified as relative percentage of the three choices of sources of raw material herbs available to the manufacturers in conjunction with the conservation status of the plant species as recorded by the International Union for Conservation of Nature (IUCN).Fiftyseven medicinal plant species (in 34 angiosperm families) were used to formulate 71 herbal recipes that are indicated for treating 14 different health conditions. The sources of raw material herbs, in relative terms, were purchase from herbal markets/suppliers(38.7%), collection from the wild vegetation (35.5%) and cultivation of some of the herbs for use (25.8%). The herbal material used included fruits, seeds, leaves, stem barks, flowers, roots and rhizomes, most of which can be sustainably harvested. Based on the IUCN records, only six (i.e. 10.5%) of the 57 plant species have been evaluated and placedin the categories of ‘Least Concern’ (Ceibapantandra, Colaacuminata, Ficusexasperata), ‘Vulnerable’ (Garciniakola, Khayasenegalensis) and ‘Endangered’ (Jatrophacurcas). Production of TOLHFs in Ogbomoso was therefore, adjudged to be sustainable with minimal potential injury on the natural flora. Medicinal plant cultivation by THMPs and herb vendors should however, be further encouraged or enforced.