Poisoning or backdoor attacks are well-known attacks on image classification neural networks, whereby an attacker inserts a trigger into a subset of the training data, in such a way that the network learns to mis-classify any input with the trigger to a specific target label. We propose a set of runtime mitigation techniques, embodied by the tool AntidoteRT, which employs rules in terms of neuron patterns to detect and correct network behavior on poisoned inputs. The neuron patterns for correct and incorrect classifications are mined from the network based on running it on a clean and an optional set of poisoned samples with known ground-truth labels. AntidoteRT offers two methods for runtime correction: (i) Pattern-based correction which employs patterns as oracles to estimate the ideal label, and (ii) Input-based correction which corrects the input image by localizing the trigger and resetting it to a neutral color. We demonstrate that our techniques outperform existing defenses such as NeuralCleanse and STRIP on popular benchmarks such as MNIST, CIFAR-10, and GTSRB against the popular BadNets attack and the more complex DFST attack.