American ginseng is a valuable medicinal plant belonging to Araliaceae family. Its roots containing ginsenosides are used as a tonic and show antidiabetic, immunotropic, antistress, antioksidant and stimulant properties. Fungal diseases are a great problem in ginseng cultivation and may significantly decrease the yields and quality of raw material. Choosing respective forecrop and chemical disinfection of soil before seeding the seeds are the main factors affecting disease infestation of plants, yields and quality parameters of roots. In the years 1994-1999 a pot experiment aiming to determine the effect of different forecrops (rue, garlic and triticale) and soil disinfection with 2% formaldehyde was conducted. Soil disinfection with formaldehyde significantly increased the number of plants survived (in a five years-long experiment) and decreased disease infestation of roots resulting in higher yields of fruits and roots. Disinfection affected neither the weight of particular roots nor their shape. Triticale as a forecrop caused a distinct increase of aboveground parts yields, fruits and roots, but did not improve the quality parameters of roots. There was observed a decrease of the yields of plants and the average weight of single roots cultivated after rue. Among three forecrops compared, triticale followed by garlic seem to be the most suitable for American ginseng production.