29 C.F.R. § 825.113 : Labor — REGULATIONS RELATING TO LABOR — WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR — OTHER LAWS — THE FAMILY AND MEDICAL LEAVE ACT OF 1993 — COVERAGE UNDER THE FAMILY AND MEDICAL LEAVE ACT — Serious health condition

(a) For purposes of FMLA, serious health condition entitling an employee to FMLA leave means an illness, injury, impairment or physical or mental condition that involves inpatient care as defined in §825.114 or continuing treatment by a health care provider as defined in §825.115.
(b) The term incapacity means inability to work, attend school or perform other regular daily activities due to the serious health condition, treatment therefore, or recovery therefrom.
(c) The term treatment includes (but is not limited to) examinations to determine if a serious health condition exists and evaluations of the condition. Treatment does not include routine physical examinations, eye examinations, or dental examinations. A regimen of continuing treatment includes, for example, a course of prescription medication ( e.g., an antibiotic) or therapy requiring special equipment to resolve or alleviate the health condition ( e.g., oxygen). A regimen of continuing treatment that includes the taking of over-the-counter medications such as aspirin, antihistamines, or salves; or bed-rest, drinking fluids, exercise, and other similar activities that can be initiated without a visit to a health care provider, is not, by itself, sufficient to constitute a regimen of continuing treatment for purposes of FMLA leave.
(d) Conditions for which cosmetic treatments are administered (such as most treatments for acne or plastic surgery) are not serious health conditions unless inpatient hospital care is required or unless complications develop. Ordinarily, unless complications arise, the common cold, the flu, ear aches, upset stomach, minor ulcers, headaches other than migraine, routine dental or orthodontia problems, periodontal disease, etc., are examples of conditions that do not meet the definition of a serious health condition and do not qualify for FMLA leave. Restorative dental or plastic surgery after an injury or removal of cancerous growths are serious health conditions provided all the other conditions of this regulation are met. Mental illness or allergies may be serious health conditions, but only if all the conditions of this section are met.

29 C.F.R. § 825.113