Kidney calcium oxalate crystals can cause great discomfort and be very stubborn! While many people battling with kidney calcium oxalate crystals are told to avoid high oxalate foods, follow a specific low-oxalate diet daily, and drink lots of water every day, it often isn’t enough. Sometimes the diets work and sometimes they don’t. For many, the diets are simply far too restrictive for them to follow each and every day.