Andrew Smith came from St Cyrus, a small town on the east coast of Scotland just north of Montrose. He qualified as a teacher, obtaining the degree Master of Arts (MA) at the University of Aberdeen. From 1867 to 1887 he was a teacher in the College Department at the Presbyterian mission station of the Glasgow Missionary Society at Lovedale, near Alice, Eastern Cape. Shepherd (1941, p. 98) described him as as "one of the ablest and most devoted teachers Lovedale ever had". In 1888 the University of the Cape of Good Hope admitted him to the MA degree on the basis of his degree from the University of Aberdeen.
During 1877-1878, and again during 1882-1887, Smith made meteorological observations at Lovedale for the Meteorological Commission of the Cape of Good Hope, which published summaries of his data in its annual reports. He used his observations as the basis of a paper, "On disturbances to thermometer readings from local causes", which was published in the Transactions of the South African Philosophical Society (1884, Vol. 3, pp. 64-68). The "local causes" affecting his thermometers included radiation and vegetation.
During his years as a teacher Smith began a study of the medicinal uses of indigenous plants and in 1885 exhibited a collection of medicinal plants at the Port Elizabeth Exhibition. The collection was accompanied by a pamphlet entitled A contribution to South African materia medica, chiefly from plants in use among the natives (Lovedale Mission Press, 1885, 23p). A second, much enlarged edition of this work was published a few years later (Lovedale, 1888, 163p), followed by a further extended third edition (Cape Town, 1895). In the second and third editions the auther identified himself as "Andrew Smith of St Cyrus", presumably to distinguish himself from the zoologist, Dr Andrew Smith*, who had earlier spent some years at the Cape.
Although Smith's knowledge of both medicine and botany were limited, his book constituted the first significant contribution to the study of indigenous medicinal plants since Dr C.W.L. Pappe*'s Florae Capensis medicae prodromus of 1850. It contained much new information, classified according to the diseases for which the plants were used by natives or colonists, and included examples of cures. An interesting chapter was devoted to the treatment of snake-bite by preparations made from Leonotus leonurus (Red Dagga), Leonotus sp. (Klipdagga), Teucrium africanum (Paddaklou) and other plants. Treatments were also described for rheumatic fever (using preparations of Salix capensis, the Cape willow); dysentery and diarrhoea (using Monsonia ovata, the Dysentery herb, and Pelargonium sp); and numerous other complaints. He described the use of Acokanthera oppositifolia (Bushman's poison bush) to make arrow poison and referred to several other poinonous plants, some of which were used as emetics or to treat snake-bite. As is to be expected, many of the remedies were unlikely to benefit patients, while others warranted scientific investigation. An example of the latter is the use of Monsonia and Pelargonium to treat dysentery, a remedy investigated by John Maberly* around the turn of the twentieth century.
Smith sent plants to P. MacOwan* for identification and in 1890 presented a collection of medicinal plants to the Albany Museum, Grahamstown. He was an early member of the King William's Town Naturalist Society (founded in 1884). He produced two further publications relating to his years at Lovedale. One was an essay on "The principles upon which Lovedale has been conducted", published in the Christian Express (1891) and reprinted at Lovedale that same year. The other was a booklet, Short papers, chiefly on South African subjects (Lovedale and Edinburgh, 1893). He bequeethed his estate for the provision of bursaries for black students at Lovedale.