I use two mobile apps daily on my iPhone that help me to track my medications, symptoms, and diet. 

mySymptoms, on the App Store

• The mySymptoms app has been the cornerstone of data tracking for all of my Crohn’s issues for many months. I believe it is only available for iOS devices, and it’s currently $2.99 and doesn’t require a subscription or cloud service.
• I use it to track all of my medications (what time I take them, what dose), as well as my bowel movements and symptoms. The BMs tracker lets you rate them on the Bristol 1-7 scale, which doesn’t necessarily reflect a lot of the types of bowel habits and products that Crohn’s patients can experience, but it is generally helpful for tracking solidity of your poop. 
• I like that you can customize your symptoms and organize how they appear on the screen to keep the most commonly used ones at the top. It does have the capability of tracking food, but I chose to use a separate app for that (see below: Cronometer).
• A friendly hint: you can export the data in CSV form, but do yourself a favor and don’t use commas in your text notes in your entries (it just gets messy when importing into Excel or Sheets). It also has an email data backup option to ensure you don’t loose your data! Make sure you plan to do this frequently. 
• I use the exported data to make charts for my GI and I to review each time I go to see her, marking different points where I may have started a new medication protocol, or got sick with a cold, or started a new food.

Cronometer, on the App Store

• The Cronometer App is free, but the subscription currently costs $34.99 per year. It operates much in the same was that mySymptoms does, allowing you to enter your daily foods and meals, tracking the time you ate them.
• I chose this app because of the detailed, managed database of nutrients and ingredients. I was struggling with my caloric intake significantly and loosing weight drastically this summer. My dietician encouraged me to start tracking various vitamins, fiber and calories to make sure I was hitting daily values that were conducive to healing my intestines.
• The database of foods is extensive, but the makers of the app do caution that in order to get the most accurate nutritional breakdown for what you eat, it’s best to search their managed list of raw ingredients and build your recipes with them. That way you can guarantee that you’re getting credit for and tracking all of the values you need. Since I’m not eating almost any prepared foods, this was an easy adjustment to make. It’s easy to search for foods to add, and to mark them as commonly used favorites. 
• It allows you to set highlighted targets for calories consumed, fiber, iron, calcium, Vitamins D, C, B12 and Folate, as well as weight loss goals (which you can also hide, which I do!). It tracks a large number of other vitamins, minerals, carbs, lipids, protein and nutrient balances. You can also track your calories burned by entering activities. 

I plan on getting an Apple Watch soon and I’m hoping to use it to track my heart rate. I’ve been lucky that my blood pressure has remained good while on this course of prednisone, but whoo! It sure can make the heart race! I don’t know if there are any Apple Watch compatible apps that allow you to enter data from your watch, but I’ll certainly update with a new post if I find any.

There are other apps out there that I decided against using for various reasons, but may be worth looking into if these two apps don’t work for you:

• GI Monitor: free, iPhone, Android
• myIBD: free, iPhone, Android 
• GI Buddy: free, iPhone, Android
• Bowel Mover Pro: $2.99, iPhone 
• Oshi: free, iPhone, Android

*I have not been compensated for this post.