Electroceuticals based on peripheral nerve stimulation offer promising treatment for refractory inflammatory diseases such as inflammatory bowel diseases (IBDs). For pediatric IBD (PIBD) patients, wireless, biodegradable miniaturized bioelectronic devices are crucial to prevent neural damage and support neural development during and after therapy. Here we demonstrate a battery-free, miniaturized neurostimulator based on biodegradable materials and capacitive-coupling wireless power transfer. The biodegradable capacitive-coupling (BCC) neurostimulator consists of molybdenum (Mo) electronic components and self-healing biodegradable polyurethane elastomer (SBPUE) encapsulations. The self-healing property of SBPUE enables a stable neural interface. Capacitive coupling wirelessly transfers high-frequency electric fields through a single capacitor between wearable transmitters and implanted BCC neurostimulators. Programmed electrical stimulation of the vagus nerve alleviates PIBD symptoms by restoring CD4