The three kinds of defect
A **manufacturing defect** means the product departed from its intended design — this particular unit was wrong. A **design defect** means the design itself is unreasonably dangerous, so every unit carries the risk. A **failure to warn** means the risk was known or knowable and the warnings or instructions were inadequate.
Which one you allege changes the evidence entirely. Manufacturing defects often turn on the product itself; design and warning cases turn on what the manufacturer knew, when, and what it did about it — which comes out through disclosure.
Causation is where cases are won and lost
You must show the defect caused your injury, not merely that you used the product and were later harmed. In pharmaceutical and toxic-exposure cases this almost always requires expert medical evidence, and sometimes evidence about general causation (can this substance cause this harm at all?) as well as specific causation (did it cause yours?).
Pre-existing conditions, alternative explanations and dose or exposure levels all get scrutinised. This is why a documented medical history from before the injury is so valuable.
Preserve the evidence — this is the step people get wrong
Keep the product itself. Do not discard, repair, or return a device or item that caused injury: it is frequently the single most important piece of evidence, and losing it can end an otherwise strong claim.
Also keep packaging, lot or serial numbers, receipts and proof of purchase, prescriptions and pharmacy records, photographs of the injury and the product, and every medical record. If a recall notice exists, keep that too.
Deadlines, and who you can claim against
Limitation periods apply and vary by jurisdiction, with discoverability rules that can extend them where harm emerged later, and special rules for minors. Do not assume you have years — get the deadline confirmed.
Potential defendants can include the manufacturer, distributor, retailer and sometimes a component supplier. Where the manufacturer is foreign or insolvent, identifying a solvent defendant within the jurisdiction becomes a central practical question.
Frequently asked questions
- Do I need to keep the product?
- Yes — keep it and do not repair, alter or return it. The product is often the central evidence, and disposing of it can end a viable claim.
- What's the hardest part of a product liability claim?
- Causation. Showing the defect caused your particular injury usually requires expert medical evidence, especially in drug and toxic-exposure cases.
- Can I claim if I bought the product second-hand?
- Often yes — liability generally attaches to the defect rather than to your purchase contract, though it can affect which parties you can pursue. Get advice on the facts.
- What if the product was recalled?
- A recall is useful evidence but is not the same as proving your claim. You still need to establish the defect and that it caused your injury — though recall documentation helps establish knowledge.
- How long do I have?
- Limitation periods vary by jurisdiction, with discoverability rules and special provisions for minors. Confirm your deadline early rather than assuming.
This guide is general information, not legal advice. Laws, costs, and procedures vary by state, province, and your specific situation — speak with a qualified personal injury lawyer about your circumstances before acting.