"Horticultural therapy is defined as the engagement of a person in planting and gardening activity as a therapeutic treatment to improve their health. "Horticultural therapy" was first used in 1948, and discussed in Taiwan in 1980. Although a few educational institutes have implemented the programs of horticultural therapy, development has been slow. Horticultural therapy is beneficial for human health, improves life quality, and conserves medical resources; thus, is worth developing and encouraging. This study reviews relevant literature from the two main research databases at the Taiwan National Central Library, National Digital Library of Theses and Dissertations in Taiwan and PerioPath Index to Taiwan Periodical Literature System. We used the following five keywords when searching the databases: horticultural therapy, horticultural treatment, gardening activities, gardening curriculum, and horticultural healing, and the preliminary search returned 343 results dating from 1980. After eliminating papers that were irrelevant, did not employ experiments or surveys, and those that were repetitive, 97 papers remained. We examined the researchers' background, study subjects, types of stimulating gardening activities, activity duration, and evaluation indices to summarize and discuss the developments and changes in horticultural therapy in Taiwan to explore future research trends. The results showed that the researchers were mainly from landscape architecture, followed by nursing and education. These results indicate that most researchers specializing in horticultural therapy are from the field of gardening. Study subjects were primarily senior people; teenagers and children became the primary subjects from 1996 to 2004. After 2005, subjects were mostly schizophrenic and mentally retarded patients. However, we found that senior people had been studied continuously; thus, because they were the first group investigated, they are the most studied group. The stimulation gardening activity most frequently employed was sowing and potting outdoor plants, followed by crafts, indoor planting, and group activities; the simpler the activities were, the easier subjects felt positive emotions and increased their confidence. The most popular activities were flower arrangement and quickly-built crafts because of the vivid colors and rapid achievement of results. The activity duration was 60 to 90 min per week; the longer the subjects participated in the activities, the more significant the effects were. The evaluation indices included physiological and psychological conditions, education, and the improvement of cognitive behavior and social emotion. Based on the results, we recommend future studies focus on workers and students requiring stress relief, while continuing to study senior groups. Also, further studies should be conducted to develop other therapeutic treatments and activities that are suitable for Taiwanese and examine these treatments thoroughly."