Viral infectious disease of the upper respiratory system is known as common cold by common folk. Medical term for this disease is acute viral nasopharyngitis. Among human diseases, this is the most common and contagious disease that affects adults and its recurrence rate is average of two to four times per year. Recurrence rate can go up to twelve times in a year if it attacks school children. When weather changes from one season to another season in tropical countries, common cold will become widespread, and it usually occurs after school holidays. November to January and March to August are the two alarming periods. Common cold in bodies can be aggravated by haze, which is released from the open burning of biomass such as paddy and wheat straws. A weakened immune system, which is mostly due to not enough sleep or rest, can do the same harm as the haze. Secondary bacterial infection of the sinuses, pneumonia and asthma is due to the untreated prolonged cases of common cold.

Most common colds are caused by the infection of virus known as rhinovirus. Coronavirus, human parainfluenza viruses, or human respiratory syncytial virus are the other types of viruses that also can cause a common colds. Types of viruses that can cause cold can go up to 200 types and most of them are already present in the environment. A resistance is never built up against to these viruses in our body is due to the variety of these viruses and also the development of new viruses. Because of this, cold quite often recurs. Before the body's immune system defeats the cold virus, it can infect the next person.

Sneezing or coughing can spread virus particle through air and when a person breathes in these particles, it can cause that person catches cold. The second ways, where a person can catch cold is through person to person contact such as shake hand, hug and etc. A cold can also be spread by accidentally touching the mouth or nose with a rhinovirus contaminated hands. Nevertheless, the most threatening is sneezing because a significantly high concentration of virus can be expelled from sneezing. The falling rate of the virus cloud expelled from sneezing can last for hours in air. The virus cloud is invisible because parts of the droplet nuclei evaporating in air. Due to the evaporating of parts of the droplet nuclei and leaving much smaller and invisible droplet nuclei in the air, the virus cloud is unable to be visualized with bare eyes. Droplets from turbulent sneezing or coughing, which have been spat on any surface, can last for hours. Surface that has been contaminated by droplets through hand contact also can last for a few hours. When the virus enters the cells of the lining of the nasopharynx , which is the area between the nose and throat, it will multiply rapidly.

One to three days is the incubation period, which is the time between becoming infected and developing symptoms. About one day before symptoms begin, that is the infectious period begins. During this time, the infected person can infect others and the infectious period will continue for the first five days of the illness. In a crowded room with the close proximity of an infected person will cause the virus spread more rapidly. That's why children get infected easily in class-rooms or playgrounds.

Sore, scratchy, and phlegmy throat together with congestion and runny nose, sneezing and coughing is the first indication of cold. Side symptoms such as muscle aches, fatigue and weakness may accompany sometimes. Heavy fever or headache, which leads to extreme exhaustion is rarely caused by colds but mostly caused by influenza, a very virulent virus. Cold in severe and rare cases may accompany symptoms of conjunctivitis such as red, itchy, or watery eyes. If infants or young children catch cold, the symptoms mentioned above may be more severe. For a sufferer who has recovered from common cold will develop immunity in his or her body to the particular virus. However, different kind of cold virus still can easily infect this person. Generally, cold usually will end after five to seven days, but residual symptoms such as coughing and sneezing can last up to one to fourteen days depending to infected person health condition.

When someone with a cold coughs or sneezes, the virus particles can travel up to 12 feet (3.7 meters) through the air. Hence, to prevent ourselves from contracting a cold from this person, the best way is to avoid contact with such person and also stay far from this person. Moreover, we should not share towels or eating utensils such as glass, bottle with someone who has a cold. If you are the one who catches cold, try to practise good hygiene such as washing your hands thoroughly and frequently after blowing your nose. Besides, you should try to avoid touching your mouth and face in order that your hands will not contaminate with droplet. To prevent from transmitting the disease to other unaffected people, you should cover your nose and mouths with handkerchief when coughing or sneezing.

However, there are medications we can take to relieve the symptoms of the cold. For the last 50 years, herbal formulation to treat common cold already available in Europe. This herbal formulation can help to ward off viral attacks and relieving the symptoms by strengthening the body's immune system. The key components of this formulation are Herba Thujae Occidentalis (white cedar leaf herb), Radix Baptisiae Tinctoriae (wild indigo root), and two Echinacea extracts, which are Radix Echinaceae Purpureae (purple coneflower root) and Radix Echinaceae Pallidae (pale coneflower root). Thujae and Baptisiae can stimulate our immune system, while Echinacea possesses antiviral properties. Our body immune system can be activated with the help of this unique herb combination. Activated immune system can increase its resistance to disease and viral or bacterial infections. This medication has been going through many clinical trials and 20 of them already published. Currently, this combination of herbs is the only phytomedicine, which is able to treat common cold. Two scientists in Germany, Erich Schaper and Albert Brummer, developed this formulation in 1923, which has been used to treat millions of patients throughout the world. There is no side-effects and safe for consumption for both babies and adults. By Alexander Chong Author of "How to cure your incurable nasal allergy without using any synthetic drugs, herbs and expensive devices". http://www.cure-nasal-allergy.com/article10.htm