Excess mucus in the airways or lungs is not healthy, and may be caused by irritants, allergens, infectious agents or certain medical conditions.

Women normally produce testosterone, which aids in reproductive function. An abnormally high or low level can cause fertility and other medical problems.

Cirrhosis refers to severe, structure-distorting liver scarring. The presence or absence of specific complications distinguish the 4 cirrhosis stages.

If your baby has a dry scalp, the best treatment starts with understanding the cause. Dry scalp is not a serious condition and responds well to home treatment.

Cuts inside the nose can be challenging to treat, but with proper care, minor nose cuts respond well to home treatment.

New skin bumps may be caused by allergies, injury or infections -- or insect bites. The latter is a likely culprit if the bumps show up in a line.

The best treatment to ease the gum swelling is specific to the cause, so talk to your orthodontist if you have swelling that persists more than a few days.

Tight quadriceps muscles can throw the hips and knees out of whack, leading to pain in both places, as well as in your lower back.

Leg weakness isn’t necessarily a problem. When you notice that your legs feel weak whenever you climb stairs, visit the doctor.

Proprioceptive neuromuscular facilitation (PNF) is a stretching technique that takes advantage of the way your nervous system works to increase flexibility.

Muscle strains and pulls are the same injury. If you strain your hamstring you'll likely hear a pop and see bruising.

The hamstring muscles are at the back of your thighs. Their primary purpose is to bend the knee.