**7. Conclusions:**

CNTs have exhibited diverse physical, chemical and mechanical properties suitable for a va‐ riety of applications. In last decade, biomedical applications of CNTs have undergone rapid progress. Their unique properties, such as, ultrahigh surface area, high aspect ratio, distinct optical properties have been applied to develop innovative, multi-functional CNT-based nanodevices for broad applications. This chapter have described the chemical and physical methods to prepare CNTs for used in medicine. With these methods, targeting molecules are attached on CNTs for targeted drug delivery, selective imaging, and other therapies. As a new type of nanomaterial, the toxicity of CNTs has been extensively investigated. To date, tremendous toxicity studies on CNTs have been published. However, the published data are inconsistent. The reason is that CNTs used in these studies vary in dispersion status, size and length of tubes, metal impurities and functionalization methods etc. Moreover, different analysis methods used in the evaluation CNTs toxicity studies also cause disparities. De‐ spite these disparities, there is a broad agreement that well-dispersed CNTs have little or no toxicity both in-vitro and in-vivo, and therefore are useful for biomedical applications. Final‐ ly, an urgent need has been proposed for long-term studies on the absorption, deposition, metabolism and excretion (ADME) of CNTs. Only after the uncertainty on CNT toxicity is resolved, the CNT-based therapeutics can be possible applied clinically.
