Preventive healthcare services keep people healthy via frequent check-ups, screening, and counseling. They primarily aid in disease prevention rather than treating an acute or chronic illness. Preventive treatment also keeps individuals productive and energetic, allowing them to work well into their retirement years. Examples of preventive care services include:

• Adult screening for blood pressure, cholesterol, and diabetes
• Cancer screenings such as colonoscopies and mammograms
• Counseling on nutrition, mental health, and tobacco and alcohol use
• Immunization and vaccination programs
• Regular screenings of pregnant women
• Pediatric screenings for hearing, vision, and developmental disorders.

There are four levels of prevention: primordial, primary, secondary, and tertiary.

The primordial level of prevention is a population health strategy defined as efforts performed to avoid future health hazards and reduce known variables to enhance disease risks. Individual exposure to risk factors is not addressed; instead, the broad determinants of health are addressed. Examples of primordial preventive activities include improving sanitation or promoting healthy lifestyles in children.

Primary prevention reduces the development of chronic illness by lowering risk factors. Risk reduction through changes in behavior or exposure is one method of primary prevention. Reduced cardiovascular risk can be achieved by lifestyle modifications such as a good diet and smoking cessation. Vaccinations, such as influenza and pneumonia vaccines, prevent severe disease in most people. Some of these preventative strategies are active and require individual engagement, while others are passive. The focus of primary prevention is typically on individual risk factors for specific illnesses.

Secondary prevention entails detecting and treating pre-clinical abnormalities. Screening techniques are frequently used in the initial stage, resulting in earlier and more cost-effective treatments. The screening process is a collaborative effort between the individual and their healthcare professionals, focusing on patient participation.

Tertiary prevention, which focuses on reversing, halting, or postponing illness, is exclusively clinical. It helps decrease the burden of disease on the patient's overall life. The patient has greater contact with the healthcare system and care providers in various roles and places (e.g., cancer patients receiving chemotherapy).