Most people tolerate generic Doryx medication reasonably well and most side effects are both minor in nature and transient. The exception to this generality relates to the effects on unborn fetuses, infants that receive the drug through their mother's milk and children under eight years old. For others, the most common side effects include chest pain, unusual swelling of different parts of the body, diarrhea, nausea, and loss of appetite. As is the case with all tetracycline-based drugs, the skin frequently becomes much more sensitive to light, making sunburn both more common and more intense; so people taking this drug should avoid prolonged exposure to the sun.