For stage 4 kidney disease, it's best to avoid herbal teas unless approved by your doctor. Instead, stick to:

White tea (lowest in oxalates)
Green tea (in moderation)
Chamomile tea (caffeine-free)
Always check with your nephrologist about specific teas and daily fluid limits. Avoid any teas with added minerals/supplements. Keep portions small and avoid sweeteners unless approved by your healthcare team.