The most common side effects of nicotine gum are related to using it improperly: soreness, hiccups, dyspepsia (upset stomach), and jaw achiness. Chewing nicotine gum quickly leads to a rapid release of the nicotine and creates more saliva. That dilutes the nicotine and makes it more likely you will swallow it. Nicotine is absorbed poorly from the stomach compared to the cheek. Worse, when nicotine is swallowed, it can lead to hiccups, gas, and nausea.
Try not to swallow for a minute or so when you start to release the nicotine. Allow it to be absorbed where it is intended—the cheek and not the stomach. The first few days are key. You may notice a burning sensation, which means you are chewing it too quickly. The same is true for lightheadedness, gas, nausea, or too much saliva. By following the instructions in the package insert, side effects can be minimized. So, begin gently.
One other point, over-chewing can lead to jaw pain. The gum is meant to be “parked” against the gum where the nicotine is best absorbed.
Less common side effects can include increased heart rate and blood pressure, oral irritation and sore, dental pain, and gas. Oral irritation and sores can be reduced by moving the gum from place to place when you park the gum (try not to use one spot), dental pain can be reduced to a degree by avoiding dentures and implants, and gas can be reduced by slowly chewing the gum and swallowing less of the nicotine.
This information is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment, and should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.