It depends on what condition the person is in. Almost everyone feels benefits of some kind in their first week of drinking celery juice in the right amount and in the right way daily. Many people even feel benefits after their first juice. It all depends on the person and their circumstances, such as their health conditions and symptoms and how toxic and overburdened their liver is with different pathogens and poisons such as pesticides, solvents, herbicides, toxic heavy metals, and all kinds of other chemicals and toxins. (See Liver Rescue for more information on what having a toxic liver means, how common it really is and how to heal your body). If someone is dealing with weight issues, if they have a lot of putrefied and rancid fats in their colon, and/or a lot of bacteria in their intestinal tract such as streptococcus, this will also affect the healing timeline.
The amount of stress someone is experiencing in their life, what else they choose to eat and drink in addition to their straight celery juice, and their other lifestyle habits will also play a role in how long it takes for someone to feel the benefits. But most people do feel a difference rather quickly. Some people who have been drinking celery juice for a long time get used to how good or how much better it makes them feel than when they weren't drinking it. Then they stop drinking celery juice temporarily, like many do, and find they don’t feel as good anymore. They realize at this point just how instrumental the celery juice was in helping them feel better.
It’s important to know that even if someone doesn’t see or feel the benefits of drinking celery juice quickly, it doesn’t mean the benefits aren’t happening. Everybody who drinks celery juice receives benefits immediately, because the healing powers of celery juice begin working immediately upon entering the body. For some people, it can take a bit of time to see or feel the benefits in a tangible way they can notice, even though the celery juice has been providing healing benefits from the first drink internally.