I can't. Senecio scandens is a Chinese herbal medicine and a spice, which has the effects of clearing away heat and toxic materials, promoting blood circulation to relieve pain, expelling wind and removing dampness, and is mainly used to treat enteritis, dysentery, rheumatalgia, toothache, traumatic injury and other diseases. Foeniculum vulgare L. is also a Chinese herbal medicine, which has the effects of promoting qi circulation and relieving pain, regulating stomach and stopping vomiting. It is mainly used to treat cold hernia, abdominal pain, testicular swelling and pain, dysmenorrhea, irregular menstruation, epigastric pain and other diseases. The efficacy of Senecio scandens is different from that of Foeniculum vulgare. If the patient blindly uses Senecio scandens or Foeniculum vulgare to treat the disease, the medicine may not be symptomatic, which is not conducive to the recovery of the disease. So Senecio can't replace fennel.