Surgery may have a number of undesirable or harmful after effects, such as infection, hemorrhage, inflammation, scarring, loss of function, changes in local blood flow, and so on. They can be reversible or irreversible, and a compromise must be found by the physician and the patient between the beneficial or life-saving consequences of surgery versus its adverse effects. For example, a limb may be lost to amputation in case of untreatable gangrene, but life is saved. Presently, one of the greatest advantages of minimally invasive surgery, such as laparoscopic surgery is the reduction of adverse effects.
Other non-surgical physical procedures such as high intensity radiotherapy may cause burns and alterations in the skin. In general, these therapies try to avoid damage to healthy tissues while maximizing the therapeutic effect.
Vaccination may have adverse effects, due to the nature of its biological preparation (sometimes using attenuated pathogens and toxins). Common adverse effects may be fever, malaise and local reactions in the vaccination site, such as eczema vaccinatum, a severe, sometimes fatal complication which may result in persons who have eczema or atopic dermatitis.
Diagnostic procedures may also have adverse effects, depending much on whether they are invasive, non-invasive or minimally invasive. For example, allergic reactions to x-ray contrasting material often occur, a colonoscopy may cause the perforation of the intestine wall, etc.
