T. domestica bears a behavior toward large intruders that may be perceived aggressive. As long as its web is undisturbed, the spider will retreat to the funnel tip and stop responding to any movement whatsoever. If the web is attacked and partially destroyed, the spider will run toward the intruder and try to confuse it with irregular movements (randomly running around it, for example). If the threat is fast enough to follow them, the spider will then walk on cast objects, including protruded body parts, in hopes of reaching soft tissue to inflict a bite. Because of its speed, it can cross even the most slippery surfaces and softened clothes rapidly. The greatest danger will be represented by T. domestica if it gets stuck between clothes and skin, both consecutively and accidentally (while occupying a sleeve of one’s shirt, for example).
Domestic house spiders deliver venomous bites on almost all occasions. Their venom is both neuro- and necrotoxic and can leave small lesions over the bitten area, similar to that of a burn. Besides causing considerable local pain, venom effects are minimal in healthy adults and may sometimes include malaise and fatigue feelings in children and elderly, but will usually wear off on the same day. The bite area is better treated with iodine and will disappear within the next three days. No medical attention is required.