An individual with a poor oral hygiene invites a host of infections and diseases like gum disease or a tooth infection, gingivitis which may all cause bitter taste in mouth. An unwanted bitter taste in the mouth may be caused by GERD or acid reflux. This is usually caused by dry mouth, which is a common symptom of menopause. GERD can usually be pinpointed as the cause of a sour or bitter taste as it typically co-occurs with heartburn and will develop soon after eating. Women who are going through menopause or are about to often mention having a bitter taste in their mouth. The unpleasant taste can develop suddenly or over longer periods of time. A metallic taste in your mouth is a type of taste disorder. Gastroesophageal reflux disease (GERD) or acid reflux may be the source of an unwanted bitter taste in the mouth.

A soapy-bitter taste is identifiable with rancidity. There appears to be a seasonal affect with the months between July and September having the highest occurrences. Rancidity is caused by a chemical development, which continues until the milk is pasteurized. Poor Oral Hygiene: This is one of the main causes of bitter taste in mouth.