The Municipal Health Office (MHO) directly provides basic health services to the people covering primary health care such as maternal and child care, family planning, nutrition, immunization program, micronutrient supplementation, communicable and non-communicable disease control services, dental care services, environmental sanitation and health education. The Rural Health Units of the municipality are composed of one Main Health Center and nine Barangay Health Stations (BHS). The Main Health Center (MHC) serves the whole municipality and is under administrative and technical supervision of the LGU. The MHC is a Basic Emergency Maternal and Obstetrical New Born Care (BEMONC) facility and complies to PhilHealth accreditation standards for OPB package, maternity care package and TB-DOTS package. The MHC is located in the urban center at San Juan in a two-storey building with a four-bed capacity.

Health human resources of the MHO is composed of one medical doctor, two nurses, nine rural health midwives, one medical technologist, one rural sanitary inspector, one dentist and one dental aide. The pool of volunteers composed of 270 Barangay Health Workers (BHWs), 184 Women Health Teams and 54 Barangay Nutrition Scholars assists the LGU medical personnel in the delivery of community health services. 

Irosin is the host of the Irosin District Hospital (IDH) which is located in San Pedro in a one hectare lot. The IDH is a 25-bed capacity Secondary Care District Hospital providing definitive care in the four basic specialties of namely medicine, surgery, obstetrics, gynecology and pediatrics. The specialties are not departmentalized and the hospital has administrative and ancillary radiology, pharmacy, dietary and laboratory services. Medical health personnel of the IDH include six doctors, 12 nurses and seven midwives.

Irosin General Hospital (IGH) is a newly established private infirmary located at Buenavista near the urban center. Services provided by the 11-bed capacity hospital are general medicine, pediatrics, obstetrics, gynecology and minor surgery. Ancillary services are laboratory, pharmacy and radiology. The IGH has 11 doctors, five nurses and one midwife.

There are five medical clinics, one dental clinic and one optical clinic registered and operating in the municipality and all are located in the urban center. The nearest tertiary level hospitals are located at Sorsogon City namely Dr. Fernando B. Duran, Sr. Memorial Hospital and the Sorsogon Medical Mission Group Hospital and Health Services Cooperative.

The health and nutrition status of the municipality has improved over the years. Incidence of malnutrition is at 12.64% among 0-5 years old and 13.78% among 6-12 years old children in 2015. Among other health development indicator is infant mortality rate is 12.4% in 2014, child mortality rate is 8.9% in 2013, and 0% maternal mortality rate in the past two years. A total of 99% of births in the municipality are delivered in health facilities in 2015. The under-five immunization rate in 2016 was 67%.

Eight of the ten leading cause of death in 2013 are non-communicable in etiology. Chronic obstructive pulmonary disease (COPD), cardiovascular diseases, cancer, septicemia and diabetes are the leading non-communicable diseases. The lingering problem on infectious diseases like tuberculosis and pneumonia is still evident as they ranked 7th and 8th in the leading causes of death in 2013 and 1st and 7th in 2012. Deaths from external cause are from accidents which ranked 6th in 2013 and 3rd in 2012.

Four of the ten leading cause of morbidity of all ages in 2013 are non-communicable and four are infectious diseases. Hypertension, intestinal parasitism, asthma and urinary tract infection are the leading non-communicable disease. Infectious diseases like acute respiratory infection, acute gastroenteritis, pneumonia and tuberculosis ranked 1st, 6th 7th and 8th respectively. Three of the leading causes of morbidity namely intestinal parasitism, skin problem and acute gastroenteritis can be attributed to sanitary conditions.

The rise in non-communicable diseases along with the existing prevalence of infectious diseases indicates that Irosin has a double burden of disease. This disease pattern indicates that even as degenerative diseases and other lifestyle-related illnesses are increasing, communicable diseases are still widely prevalent.