Yes drinking celery juice everyday is safe and it's very healthy for you too.
I drink two glasses of celery juice that I make at home everyday one for breakfast and one for lunch and I've seen improved health and energy when drinking celery juice everyday.
Celery Juice is very high in vitamins and minerals and also anti-inflammatory, detoxifying and gut-friendly which is all good for your health.
I also eat 2 celery sticks per day as well because I love celery and I add some peanut butter to the celery sticks and it makes a lovely and healthy snack.