Hi. I just ran into your post. Mega doses of vitamin C are safe. I personally fifteen up to twenty thousands milligram a day. And I increase that dosage whenever I feel something bad coming. The only consequence is I never get sick. Let me add that this is no prescription of any kind. If you are ill, seek the help of a medical doctor. I'm just sharing my experience. I never suffer from cough or flu or headache or anything. I can't remember when last I was sick. To unclog your bowels, take a teaspoon of vitamin C powder with 8oz of water every fifteen minutes until you start feeling things move in your G.I tract. Generally you will feel bloated for about 2 hours. Then you will start emptying your bowels. But after that the feeling is great. It's amazing how you feel when you get the toxic waste out of your system. Besides this, you can combine 3 tablespoons of organic castor with 4 tablespoons of freshly squeezed lemon juice and drink it only empty stomach. Then drink a glass of hot water (not so hot as to burn your throat) every 20 minutes. But make sure you're not going anywhere that day. Because you will spend a lot of time in the bathroom. Another option is to get yourself some liquid magnesium citrate at any CVS (not a Walgreens because they mark the price higher). It'll cost you less than 3 bucks. Chug the bottle and wait for result. Depending on how your body works it may kick in within 30 minutes or after 6 to 7 hours. If you feel like passing gas after chugging the liquid magnesium citrate, do it on a toilet seat. Because in the place of gas, feces may come out. One more option: get you some triphala powder to mix with water and drink twice a day. Hope you will find this helpful. May you inclog those bowels and poop to your great satisfaction..😉 Oh! Considering how serious your problem seem to be, I have the neat impression that your liver isn't working properly. Because a weak liver results in various digestive problems. I would suggest you help your liver with fresh homemade dandelion juice or dandelion and milk thistle tea or beet root juice mixed with dandelion juice. Regular coffee enemas will also help your liver to release toxins in your small intestine so that it may work better to improve your health. I would appreciate to hear from you. Wish you good health...