According to the Mayo Clinic, an online medical research group of around 2,500 physicians worldwide and is known for its online diagnosis and treatment of diseases, it may actually cause more harm than good.

"Most OTC cough medicines contain a mixture of decongestant, antihistamine, pain reliever, cough suppressant or a combination of these drugs. These combinations are meant to treat many symptoms at once but all of them have potential side effects," the organization said.

It pointed out that those with decongestants may produce a narrowing of blood vessels leading to the clearing of nasal congestion. However, it may also be potentially dangerous to patients suffering from hypertension since decongestants are known to increase blood pressure.

While cough remedies with antihistamines prevent the symptoms of hay fever and other types of allergy as well as relieve sneezing and runny nose, the Mayo Clinic said, elderly patients were reported to feel fainting, confusion or irritability when they take the medicine.

PharmacyHealth, a research institution that monitors US approved prescription drugs and popular health supplements noted some of the more common side effects of cough medicines include drowsiness, dizziness, headache, loss of appetite, stomach upset, blurred vision, restlessness, irritability and dry mouth and nose. "Some cough remedies may also cause irregular heartbeat, chest pain, ringing in the ears, heart pounding and breathing difficulty," PharmacyHealth revealed.

Children are known to experience nightmares, unusual excitement, nervousness, restlessness, or irritability when given cough medicines.

Cough medicines are either suppressants, meaning it suppress the body’s urge to cough, or expectorants, which loosen the mucus or phlegm in the lungs. One of the popular ingredients of suppressants is codeine, a narcotic derived from opium. It is known to induce physical and mental dependence.

Dr. William Elwood, who conducted a study on the misuse of cough syrups for the Texas Commission on Alcohol and Drug Abuse, said codeine can likewise induce fatigue and loss of coordination. "Codeine affects the central nervous system and is an effective cough suppressant. Common side effects include drowsiness, dry mouth, constipation, urinary retention, confusion, itchiness, and – of course – addiction," Elwood said.

Another substance found in most cough syrups is dextromethorpan. While the United States’ FDA said that it is a generally safe and effective, cough suppressant when formulated properly, can also cause adverse effects such as brain damage, seizure, loss of consciousness and irregular heartbeat.

The adverse side effects of OTC cough medications have led people to go for non-medical treatments like taking fluids such as water or calamansi juice. Another safe alternative to chemical-based cough medicines is using natural cures such as lagundi leaves.

"If I think there is an infectious cause to the cough, I work to build up the immune system, either with herbals or acupuncture," Dr. Mark C. Merlin, holistic and integrative medicine specialist in Atlanta, said.

Most coughs, Merlin explained, are due to common cold and are not serious. They usually disappear from two to three weeks. He advised rest, plenty of fluids and the use of natural or herbal cure for a healthier body constitution.