Final answer:
The fourth nursing intervention for excessive, foul-smelling red lochia is administering antibiotics to address potential infection, alongside monitoring and emotional support.
Step-by-step explanation:
The fourth nursing intervention for a client with excessive lochia that is red and has a foul-smelling odor is administering antibiotics. This condition may indicate an infection, and antibiotics are used to treat bacterial infections. It's essential to monitor the patient's response to the medication and watch for any signs of a systemic infection. Providing emotional support is also important, as dealing with postpartum complications can be stressful and challenging for the patient.