When nature calls, it's difficult to ignore the urge to use the bathroom. But sometimes using the same expression over and over again can become repetitive. Here are some synonyms for "call nature": answer the call of nature, heed the call of nature, attend to personal needs, take a bathroom break, use the lavatory, visit the restroom, go to the loo, relieve oneself, empty one's bladder/bowels, answer a primal urge, take a bio break, take a comfort break, take a pit stop, use the facilities. Using these different phrases can add variety to your language and make it more interesting.