The medicinal leech is vulnerable to temperature, smell, magnetic field, sounds, water and air movements, chemicals substances, gravity and electric field. Leech sensory organs are scattered around body surface. These are called mechanoreceptors (sensory cells). Thus, before the treatment, the skin should be cleaned with mild soap. Do not use any perfume in two days before the treatment date. One should not apply creams, balms or ointments on the therapeutic area.
