If the design of a product or product component is in issue in a product liability action, the design shall be presumed to be reasonably safe unless, at the time the product left the control of the manufacturer, a practical and technically feasible alternative design was available that would have prevented the harm without significantly impairing the usefulness, desirability, or marketability of the product. An alternative design is practical and feasible if the technical, medical, or scientific knowledge relating to safety of the alternative design was, at the time the product left the control of the manufacturer, available and developed for commercial use and acceptable in the marketplace.
2-2104.No practical and feasible alternative design; presumption.
Article II. Civil Practice · Part 21. Product Liability · Last amended 1995 · Last verified July 20, 2026
In one sentenceSection 2-2104 presumes a product's design is reasonably safe unless a practical, technically feasible alternative design existed when the product left the manufacturer's control that would have prevented the harm without significantly hurting the product's usefulness or marketability.
Full Text of 735 ILCS 5/2-2104
Plain-English Summary
Section 2-2104 addresses design defects specifically. When a product's or component's design is at issue in a product liability action, the design is presumed reasonably safe. To overcome that presumption, the record has to show a practical and technically feasible alternative design was available at the time the product left the manufacturer's control — one that would have prevented the harm without significantly impairing the product's usefulness, desirability, or marketability.
The section defines what makes an alternative design "practical and feasible": the technical, medical, or scientific knowledge about the alternative's safety had to be available and developed for commercial use, and the alternative had to be acceptable in the marketplace, all as of the time the product left the manufacturer's control.
The timing anchor matters. The presumption and its rebuttal are both measured against what was available when the product left the manufacturer's hands, not against what might be known or feasible by the time of trial.
Frequently Asked Questions
What must a plaintiff show to overcome the design-safety presumption?
That a practical, technically feasible alternative design was available at the time the product left the manufacturer's control, and that it would have prevented the harm without significantly impairing the product's usefulness, desirability, or marketability.
What does "practical and technically feasible" mean under this section?
The alternative design's safety had to rest on technical, medical, or scientific knowledge that was available and developed for commercial use, and the alternative had to be acceptable in the marketplace, as of the time the product left the manufacturer's control.
At what point in time is the alternative design evaluated?
At the time the product left the control of the manufacturer — not at the time of the injury or the time of trial.
Does an alternative design have to be perfect to count?
The section doesn't require perfection. It requires that the alternative would have prevented the harm without significantly impairing the product's usefulness, desirability, or marketability.
Can an alternative design defeat this presumption if it makes the product significantly less useful?
No. The section requires that the alternative not significantly impair the product's usefulness, desirability, or marketability for it to count against the presumption of a reasonably safe design.
Amendment History
(Source: P.A. 89-7, eff. 3-9-95.)
Source & verification. Section text and amendment history are
reproduced verbatim from the Illinois Compiled Statutes, published by the
Illinois Compiled Statutes, Illinois General Assembly / Legislative Reference Bureau. Last verified July 20, 2026.
· Official source
Also known as: alternative design defense illinois product liabilityfeasible alternative design presumption illinoisdesign defect product liability illinois