Background: In France, hospital pharmacists perform medication order reviews during patients' hospital stays. This activity can be centralized in the pharmacy or carried out directly in the ward, in collaboration with the healthcare team. During this review, pharmacists can make recommendations to optimize therapeutics. Since 2006, they can document their interventions, via the national Act-IP© observatory. Aim: To determine the characteristics of pharmacists' interventions and their acceptance by physicians in French hospitals. Method: A 6-year observational study of pharmacists' interventions documented on the Act-IP© French observatory between 2009 and 2014 was performed. Multiple logistic regression was undertaken to determine the predictors of physicians' acceptance of interventions. Results: A total of 194,684 pharmacists' interventions were documented and concerned mainly "dosage adjustment" (25.6%). These interventions were mostly related to drugs from the central nervous system (23.7%). Seventy percent of pharmacists' interventions were accepted by physicians. Acceptance rate was higher when conducted by a pharmacist regularly practicing in the ward (ORa = 1.60, CI 95 [1.57-1.64]). Physicians' acceptance was significantly associated with (1) ward specialty: emergency (ORa = 1.24, CI 95 [1.14-1.35]); (2) type of intervention: "drug discontinuation", "drug switch" (ORa = 1.15, CI 95 [1.12-1.19]) and "addition of a new drug" (ORa = 1.15, CI 95 [1.12-1.19]); (3) drug group: antineoplastic and immunomodulators (ORa = 3.67, CI 95 [3.44-3.92]). Conclusion: This 6-year longitudinal study highlights the role of clinical pharmacists, and particularly the impact of those integrated into wards. This was found to improve intervention acceptance, potentially through collaboration with physicians in pursuit of patient care and drug safety.