Abstract: OBJECTIVE To observe the effect of spleen appetizer formula (SAF) containing serum (SAF-CS) on Ca²⁺， MLC and the p-MLC in human gastric smooth muscle cells (HGSMCs) and the relationship with Ghrelin receptor (GHSR)， and to explore the mechanism of SAF for treating anorexia. METHODS HGSMCs were cultured， while the low， medium and high concentrations of SAF-CS were prepared; Confocal laser detection method and Western blot were used to test the effects of SAF-CS on Ca²⁺， MLC and p-MLC; The GHSR existed on the surface of HGSMCs was blocked and the normal rgulation of intracellular and extracellular Ca²⁺ were abolished to study the mechanism of SAF-CS effect on p-MLC. RESULTS Low， medium and high dose group of SAF-CS up-regulated the relative fluorescence intensity of Ca²⁺ in a certain time range (P<0.01， P<0.05) in HGSMGs; low， medium and high dose group of SAF-CS markedly increased the level of p-MLC at 10 min in HGSMCs (P<0.01， P<0.05); (D-Lys3) -GHRP-6， Thapsigargin， D-HBSS solution significantly inhibited the up-regulation of p-MLC by the high dose of SAF-CS at 10 min(P<0.01). CONCLUSION The SAF-CS may increase intracellular Ca²⁺ levels and promote phosphorylation of MLC via activating GHSR.