The first common, and most serious, cause of sulfur burps is an infection from Helicobacter pylori or Giardia. Helicobacter pylori is a bacterium that can cause serious infection and ulcers within your stomach. Giardia is a parasite that makes its home in your lower intestine and reproduces to cause serious stomach problems. The most common ways to introduce either of these infections is through unclean water sources or poor hygiene and oral-fecal transmission. Sulfur burps can be a symptom of both of these infections.