Studies by health experts and reputed doctors have revealed that antibiotics cause more harm than good. By this, it does not mean that antibiotics do not do any good at all. They are good only if you take them when you are sick enough to need them. Of course, if you have undergone a surgery, you need antibiotics so as to ensure that no infection develops at the activated spot. Similarly, you need to take them when you have severe infections such as pneumonia or Pharyngitis due to Strep Throat. If you have common colds with cough, sneezing, etc., antibiotics are not necessary at all.
The problem is that there are many bacteria that are antibiotic-resistant also. They may survive the antibiotics you take and since they are quite strong, they may multiply more quickly than you expect.
It is true that the common cold you may be suffering from is viral. But common cold is not bacteria. So, you can not treat it with antibiotics. Further, antibiotics are capable of killing all types of bacteria in your body and this means that they will kill both the bad bacteria and the good bacteria. The gut in your system is full of good bacteria and only with their help, you are able to get your food digested. The number of such good bacteria in your body is more than the number of cells in your body. These good bacteria that are otherwise known as "intestinal flora" bestow immunity health benefits on you. If you study about them, you will come to know these intestinal flora can ferment the energy substrates that remain unused, they can train body's immune system, can keep the growth of species that are harmful at bay, can regulate the gut's development, produce vitamins like Biotin, Vitamin K, etc. and also the required hormones that direct the body in the process of proper storage of fats.
By taking antibiotics when not needed, you will be killing these good bacteria. Instead, you should ask your doctor the ways to supply your body with probiotics. The best source of probiotics are fermented foods. Even fermented vegetables are good for improving the amount of good bacteria in your gut.
Simply put, you should take antibiotics only if you suffer from life-threatening illnesses or if you have undergone a surgery. You should never forget the fact that antibiotics are not capable of killing viruses. If you eat the right types of foods including fermented foods and do your exercises regularly, you may not fall sick at all and so, you may never think of taking antibiotics. Of course, your fermented foods will keep supplying your body with probiotics that may help you to have a good amount of good bacteria in your gut.