Please consult with a medical professional prior to including this tea in your diet if you are on medication, are pregnant, or nursing. Papain in papaya leaf has been known to cause allergic reactions in some. Note that papaya is likely safe for most people when taken by mouth in moderate amounts, either in food or as medicine. Papaya can be possibly unsafe when consumed in large amounts or when taken as an oral medicinal. As papaya may be an abortifacient (a substance that induces abortion), its consumption during pregnancy is not advised.
Ginger is also generally safe, but some side effects may be experienced if consumed in excess (approximately 4 grams or greater). The National Center for Complementary and Integrative Health (NCCIH) notes that ginger may cause gas and bloating, abdominal pain/stomachache, or diarrhea. Ginger can increase bile production, so it is a good idea to check with your doctor before consuming ginger tea if you have a history of gallbladder problems.
Drinking ginger tea may also trigger heartburn or stomach upset, similar to the response you might experience after eating spicy foods. Ginger may help lower blood pressure, so lightheadedness is another potential side effect. Ginger also contains salicylates, which can be contraindicated for those with bleeding disorders.