**Abstract**

The plant kingdom is considered the most important source of medicinal chemicals. *In vitro* culture techniques are being considered a promising alternative to traditional agricultural processes to improve medicinal plants multiplication and their production of pharmaceutical compounds. In this chapter, several *in vitro* culture strategies are discussed to improve secondary metabolites production, including (1) plant kingdom as a source of medicinal chemicals, (2) *in vitro* culture of medicinal plants, (3) culture media optimization, (4) application of suspension cell culture for production of secondary metabolites, (5) elicitation to enhance the productivity of the culture, (6) precursor intermediates feeding, (7) selection of high-yielding cell lines, (8) overexpression of genes that control the production of bioactive compounds, and (9) scale-up production. Also, challenges that hinder the *in vitro* culture of medicinal plants using different techniques and the use of those techniques to produce pharmaceutical compounds are discussed in this chapter, including (a) secondary metabolites toxicity, (b) low growth rate, (c) culture browning, (d) limitation in the application of transformation, (e) somaclonal variation, and (f) vitrification. Therefore, the principal objective of the current chapter was to shed light on the studies on some medicinal plants and the used protocols to overcome some difficulties in terms of *in vitro* propagation that maximize their economic values.

**Keywords:** *In vitro* plant culture, medicinal plants, pharmaceutical compounds, tissue culture, medicinal chemicals
