Most Likely Effects

• Passion flower causes drowsiness and sedation, as well as dizziness and slower thinking. Other side effects include rapid heartbeat, nausea and vomiting.
  
  

Increased Bleeding

• The herb may increase the risk of bleeding, particularly when taken with anticoagulants, such as warfarin or heparin, and anti-inflammatory drugs such as ibuprofen and aspirin.
  
  

Drowsiness-Causing Drugs

• Using passion flower with other drugs that cause drowsiness can increase this effect. Examples include alcohol, benzodiazepines, barbiturates, narcotics and some antidepressants.
  
  

Other Drug Interactions

• Passion flower may increase the effects of monoamine oxidase inhibitory (MAOI) drugs, and increase the risk of low-blood pressure when taken with tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs).
  
  

Allergic Reaction

• Rarely, some people may have an allergic reaction to passion flower. Signs of an allergic reaction include rash or hives, itching, dizziness, swelling and difficulty breathing.