Chemo Side Effect Tracker
Free iPhone app

Side effects, tracked the way your oncologist grades them.

Log how you feel in about a minute a day. The app turns your answers into estimated toxicity grades, so your care team sees exactly what happened between visits, on one screen.

Created by an oncologist to help patients. Free, no account, and your information stays on your iPhone.

See what it does

Want to know when it's ready? Email support@chemosideeffecttracker.com and we'll let you know.

Thursday, Oct 9
Good afternoon, Maria
FOLFOX
Some moderate side effects
Keep logging and show the Doctor view at your next visit.
Treatment
Planned treatmentCycle 5 of 12
This cycleDay 8 of 14
Next treatmentIn 6 days
Side effects · cycle 5
Numbness / tingling
Diarrhea
Fatigue
Nausea
Free for everyone

Everything you need between visits

Questions your team grades by

Each symptom asks the real grading questions in plain words, like "how many more bowel movements than your normal?" or "does it make buttons or writing hard?"

Estimated CTCAE v6.0 grades

Your answers map to the National Cancer Institute's current grading criteria, color-coded from mild to severe.

Built for your regimen

Choose your treatment and the app picks the side effects that matter for it. FOLFOX, FOLFIRINOX, carboplatin combinations, immunotherapy, and more.

Where you are in your cycle

Day of cycle, typical phases like the low blood count window, and a countdown to your next treatment.

Red flags you can't miss

A fever of 100.4°F or higher, an ER visit, or very high blood pressure brings up a clear "call your care team" alert.

Planned or ongoing treatment

Track "cycle 5 of 12," or time on treatment for therapy that continues as long as it's working.

Why it matters

Tracking side effects between visits makes a difference

Better quality of life, longer survival

In a randomized trial, people on chemotherapy who reported their symptoms between visits had better quality of life and lived longer than those who didn't (Basch et al., JAMA, 2017).

Memory blurs the details

Two or three weeks between appointments is a long time. Logging as you go means your care team sees what really happened, not just what you remember in a short visit.

Grades guide decisions

Oncologists use toxicity grades to decide when to adjust treatment. Clear, graded information helps your team make those calls with you.

Prepared for Dr. Patel
Patient-reported · est. CTCAE v6.0 grades
FOLFOX
For clinicians: Use clinical judgment and verify all information, including outside labs.
Fever ≥100.4°F ×1 (max 101.2°F)
Worse than cycle 4: neuropathy Grade 1 → 2
Cycle Symptom2345 Numbness / tingling1112 Cold sensitivity1212 Diarrhea1202 Fatigue1121 Nausea2111
NoneGrade 1Grade 2Grade 3
Share PDF
For your appointment

One screen your oncologist can read in seconds

Hand over your phone, or send a one-page PDF. The Doctor view shows only what matters: a few key points, then every side effect color-coded by grade, cycle by cycle.

  • Addressed to your oncologist by name, if you add it
  • Up to three high-yield points: fevers, ER visits, Grade 3 side effects, anything getting worse
  • Worst grade per cycle, so cumulative effects like neuropathy stand out
  • Clearly marked as patient-reported, for your care team to verify
  • One-page PDF to attach to a patient-portal message, email, or text
  • Ask your clinic to connect it to your medical record, whatever system they use
On-device AI, with guardrails

Just describe how you feel

Type or say something like "five loose stools today and my fingers tingle when I button my shirt." The app suggests the matching answers, each quoting your own words, and you confirm before anything is saved.

  • Runs on your iPhone. Your words aren't sent to any AI service
  • Nothing is saved until you review it
  • Never gives medical advice or suggests treatment changes
  • Works with Siri: "Log how I feel in Chemo Tracker"
How are you today?
Describe how you feel
5 loose stools today and my fingers tingle when I button my shirt
Fill in from my words
Here's what I understood. Check each one:
DiarrheaGrade 2
From your words: "5 loose stools today"
Numbness / tinglingGrade 2
From your words: "my fingers tingle when I button my shirt"
Use these answers
Getting started

Set up in about a minute

Pick your treatment, choose whether it has a set number of cycles or is ongoing, and enter when your current cycle started. Add your oncologist's name if you like, and your Doctor view is addressed to them.

  • Your regimen's usual side effects are chosen for you. Add or remove any
  • Oxaliplatin regimens also ask about cold sensitivity, separately from numbness
  • Connect Apple Health and Calendar right away, or later. Both are optional
You're all set, Maria
✓Saving your treatment plan
✓Building your cycle schedule
✓Preparing your Doctor view for Dr. Patel
Optional: connect these now, or anytime later in Settings.
Apple HealthSee your sleep, steps, weight and blood pressure next to your side effects.
Connect Apple Health
CalendarAdd your expected treatment dates, with a reminder the day before.
Add treatment dates
Go to Home
Connected

Your whole picture, in one place

Apple Health

Sleep, steps, resting heart rate, and weight, with 7-day trends next to how you feel. A rising heart rate or weight loss is flagged.

Withings and other devices

Scales, blood pressure cuffs, and thermometers that sync to Apple Health show up automatically.

This cycle vs. last

A day-by-day chart of side effects and activity, so you can see which days are hardest and plan around them.

Calendar reminders

Add expected treatment dates to your iPhone Calendar, with a reminder the day before.

Siri and Shortcuts

"No side effects today," "Log my temperature," or "Show my doctor view," hands-free.

Light or dark

A calm design that follows your iPhone, or pick light or dark.

Private by design

Your health information never leaves your phone unless you send it

No accountNo sign-up, no password, no email needed.
Stays on your iPhoneNever uploaded to any cloud, in line with Apple's rules for health apps. We don't run servers.
No ads, no trackingNo analytics or advertising tools.
Delete anytimeOne tap in Settings erases everything.

Read the full privacy policy.

What's next

Coming later

Frequently asked questions

Is it really free?

Yes. No subscription, no ads, and no in-app purchases.

Who made this app?

It was created by a practicing oncologist to help patients keep track of side effects between visits and share a clear picture with their care team.

Does it replace my care team or give medical advice?

No. It records what you report and estimates grades for your care team to review. It never recommends treatment or dose changes. For urgent symptoms, call your care team or 911.

What are CTCAE grades?

The Common Terminology Criteria for Adverse Events (CTCAE) is the National Cancer Institute's standard for describing how severe a side effect is, from Grade 1 (mild) to Grade 5. The app estimates Grades 1–3 from your answers; urgent events are flagged separately.

Which treatments does it support?

Common chemotherapy and immunotherapy regimens, including FOLFOX, FOLFIRI and FOLFIRINOX (with or without bevacizumab or cetuximab), gemcitabine with nab-paclitaxel, carboplatin combinations with pembrolizumab, AC, TC, paclitaxel, capecitabine, and immunotherapy. "Other" lets you choose your own symptoms.

Is there an Android version?

Not yet. The app is for iPhone.

Coming soon to the App Store

Chemo Side Effect Tracker is free for iPhone. Created by an oncologist to help patients.