According to experts based in last researches, the usage of antibiotics for acne may increase common illness or diseases, what it was demonstrated by an experiment in which a group of individuals that was treated with antibiotics for acne for more than six weeks (all of hem were volunteers). After the experiment, this group was more than twice as likely to develop an upper respiratory tract infection within one year as individuals with acne who were not treated with antibiotics. The overuse of antibiotics, explain experts, will lead to resistant organisms and an increase in infectious illness. There have been, however, few studies about people who have actually been exposed to antibiotics for long periods and there the importance of this one. According to experts, the ideal people to study consequences of using antibiotics for acne are patients with acne (an inflammatory disease involving the sebaceous glands of the skin; characterized by papules or pustules or comedones) , who use for long-term antibiotic therapy, representing a unique and natural population in which to study the effects of long-term antibiotic use. A group of experts from the School of Medicine of the University of Pennsylvania, Philadelphia, identified individuals diagnosed with acne between the years 1987 and 2002, aged 15 to 35 years, in a medical database in the United Kingdom (UK). The researchers searched information such as how often individuals were likely to see a physician, and compared the incidence of a common infectious illness, upper respiratory tract infection (URTI), in individuals treated with antibiotics for acne and those whose acne was not treated with these medications. Experts reported that “within the first year of observation, 15.4 per cent of the patients with acne had at least one URTI, and within that year, the odds of a URTI developing among those receiving antibiotic treatment were 2.15 times greater than among those who were not receiving antibiotic treatment”.