Allergy:is a response of the body's inmune system to a normally harmless substance such as pollen,food or dust.The body has an automatic response to what it sees as a a threat.Examples of allergies: pollen allergy,food allergy,cockroach allergy ,etc.

Anemia( also anaemia).a medical condition in which somebody has too few red cells in their blood ,making them look pale and feel weak.

Infectious disease: also known as transmissible diseases or communicable diseases, comprise clinically evident illness (i.e., characteristicmedical signs and/or symptoms of disease) resulting from the infection, presence and growth of pathogenic biological agents in an individual hostorganism. In certain cases, infectious diseases may be asymptomatic for much or even all of their course in a given host. In the latter case, the disease may only be defined as a "disease" (which by definition means an illness) in hosts who secondarily become ill after contact with an asymptomatic carrier.

Cancer: a disease caused by an uncontrolled division of abnormal cells in a part of the body. It also refers to a malignant growth or tumour resulting from such a division of cells.

Diabetes: a disorder of the metabolism causing excessive thrist and the production of large amount of urine. The diabetes mellitus is the commonest form of diabetes, it is caused by a deficiency of the pancreatic hormone insulin which results in a failure to metabolize sugars and starch.

Chickenpox: an infectious desease that causes a slight fever and red spot in the skin.

Stroke: a sudden change in the blood supply to a part of the brain, sometimes causing a loss of the ability to move particular parts of the body.