Our previous report revealed that <i>Gardenia jasminoides</i> (GJ) has protective effects against acute pancreatitis. So, we examined whether aqueous extract of GJ has anti-inflammation and antifibrotic effects even against cerulein-induced chronic pancreatitis (CP). CP was induced in mice by an intraperitoneal injection of a stable cholecystokinin (CCK) analogue, cerulein, six times a day, four days per week for three weeks. GJ extract (0.1 or 1[Formula: see text]g/kg) or saline (control group) were intraperitoneally injected 1[Formula: see text]h before first cerulein injection. After three weeks of stimulation, the pancreas was harvested for the examination of several fibrotic parameters. In addition, pancreatic stellate cells (PSCs) were isolated using gradient methods to examine the antifibrogenic effects of GJ. In the cerulein-induced CP mice, the histological features of the pancreas showed severe tissue damage such as enlarged interstitial spaces, inflammatory cell infiltrate and glandular atrophy, and tissue fibrosis. However, treatment of GJ reduced the severity of CP such as pancreatic edema and inflammatory cell infiltration. Furthermore, treatment of GJ increased pancreatic acinar cell survival, and reduced pancreatic fibrosis and activation of PSC <i>in vivo</i> and <i>in vitro</i>. In addition, GJ treatment inhibited the activation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated protein kinase (ERK) in the PSCs. These results suggest that GJ attenuated the severity of CP and the pancreatic fibrosis by inhibiting JNK and ERK activation during CP.