Should I pack full-sized bottles?

No. Bring exactly what you need for the duration of the trip plus two days extra. If you need more, buying at a local pharmacy is part of the travel experience.

Where should I keep the kit?

Keep it in your 'go-bag' or carry-on. If you have to check a bag, this kit must remain with you at all times.

So pack a family travel emergency kit that actually works

An effective travel emergency kit is not a massive medical bag; it is a compact, organized pouch containing only the non-negotiable items for common travel ailments and minor injuries. Focus on medication doses for each family member, basic wound care, and digital backups of medical documents.

Inventory your personal medication. Pack a 7-day supply of any daily prescription meds in their original bottles. Carry these in your personal item, not checked luggage, to ensure you never lose access to them if a bag is delayed.
Standardize the 'sick kit'. For a family of four, include: 20 ibuprofen tablets (adult/child versions), 15 antihistamine pills (for allergies or bug bites), 10 hydration salt packets, and 2 thermometers. Throw in 5 anti-nausea chews for travel sickness.
Prepare the 'oops' gear. Limit wound care to: 10 assorted adhesive bandages, 5 antiseptic wipes, and one small tube of antibiotic ointment. Anything bigger requires a pharmacy visit or a clinic.
Digitize your medical lifeline. Create a secure cloud folder (e.g., Google Drive or iCloud) containing photos of every family member's current prescriptions, vaccination records, and front/back copies of your travel insurance policy.

Should I pack full-sized bottles?: No. Bring exactly what you need for the duration of the trip plus two days extra. If you need more, buying at a local pharmacy is part of the travel experience.
Where should I keep the kit?: Keep it in your 'go-bag' or carry-on. If you have to check a bag, this kit must remain with you at all times.