Helicobacter pylori, once settled in the stomach and duodenum, can cause chronic inflammation of the gastric mucosa, leading to reduced stomach digestive function. Over time, this may lead to chronic gastritis, gastric ulcers, and even cause gastric cancer. So, what are the symptoms of Helicobacter pylori infection? In cases of mild infection, where the bacteria count is low, there might be no obvious symptoms, with only bad breath occurring. If a high bacteria count causes an inflammatory reaction in the gastric mucosa, symptoms can include stomach bloating, stomach pain, acid reflux, a feeling of fullness in the stomach, along with nausea and bad breath.