Different measures are recommended to reduce pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). We conducted a study in patients with ERCP treated with rectal diclofenac or lactated Ringer's solution, or both interventions, to assess whether there is a decrease in the number of cases of post-ERCP pancreatitis. A mixed cohort study involving 1,896 patients from 2009 to 2018. Up to June 2012 without treatment (Group I). Subsequently, 100mg of rectal diclofenac (Group II). Since 2016, lactated Ringer's solution 200ml/hour during the procedure and 4hours after it, in addition to 500ml over 30minutes when the pancreas was cannulated (Group III). Since 2017, lactated Ringer's solution plus Diclofenac (Group IV). There were 725 patients in group I, and 530, 227 and 414 patients in groups II, III and IV, respectively. Factors predisposing to post-ERCP pancreatitis and post-ERCP pancreatitis cases that were defined by consensus criteria have been collected. There were 65 cases of post-ERCP pancreatitis (3.4%); 2.9%, 3.4%, 3.1% and 4.3% in groups I, II, III and IV, respectively (P=.640). In group I, there was 4.2% of post-ERCP pancreatitis in naïve papillae and 4%, 4.9% and 6.3% in groups II, III and IV, respectively (P=.585). The severity of post-ERCP pancreatitis and adverse effects were similar in all groups. 38.4% were high-risk patients. There were also no differences in post-ERCP pancreatitis in this group (P=.501). In this work, no benefit was obtained with diclofenac plus hydration in reducing the number and severity of cases of post-ERCP pancreatitis nor with the other prophylactic measures.