The objective of a three-year-lasting field experiment led on silty-loam soil was to study the effects of drip irrigation and Asahi SL (Atonik) application on Mentha x piperita yield and quality. In the experiment there were used drip irrigation with T-Tape (in 10 days intervals) as well as Asahi SL (0.1%) spraying performed twice a year (before the first and the second cutting). The obtained results indicate that peppermint requires irrigation management in order to achieve high yield. Water deficit results in decrease of plant growth, essential oil accumulation and alters plant morphology. Natural growth regulator – Asahi SL application affects the essential oil content and increases the herb yield.